Completely revamp expression engine.

2026-04-16 06:18:47 +02:00 · 2024-05-29 22:55:11 -04:00
parent 7728e09337
commit d2b43605ad
22 changed files with 2716 additions and 1654 deletions
--- a/src/custom.h
+++ b/src/custom.h
@@ -166,6 +166,10 @@

 #define PASSTHRU_LEN 32

+#define MAX_RECURSION_LEVEL 1000
+
+#define MAX_FUNC_ARGS 64
+
 #define PSBEGIN "# rem2ps begin"
 #define PSEND   "# rem2ps end"

--- a/src/custom.h.in
+++ b/src/custom.h.in
@@ -166,6 +166,10 @@

 #define PASSTHRU_LEN 32

+#define MAX_RECURSION_LEVEL 1000
+
+#define MAX_FUNC_ARGS 64
+
 #define PSBEGIN "# rem2ps begin"
 #define PSEND   "# rem2ps end"

--- a/src/dorem.c
+++ b/src/dorem.c
@@ -1268,20 +1268,28 @@ int DoSatRemind(Trigger *trig, TimeTrig *tt, ParsePtr p)
 {
    int iter, dse, r, start;
    Value v;
-    char const *s;
-    char const *t;
+    expr_node *sat_node;
+    int nonconst = 0;

-    t = p->pos;
+    sat_node = ParseExpr(p, &r);
+    if (r != OK) {
+        return r;
+    }
+    if (!sat_node) {
+        return E_SWERR;
+    }
    iter = 0;
    start = trig->scanfrom;
    while (iter++ < MaxSatIter) {
 	dse = ComputeTriggerNoAdjustDuration(start, trig, tt, &r, 1, 0);
 	if (r) {
+            free_expr_tree(sat_node);
 	    if (r == E_CANT_TRIG) return OK; else return r;
 	}
 	if (dse != start && trig->duration_days) {
 	    dse = ComputeTriggerNoAdjustDuration(start, trig, tt, &r, 1, trig->duration_days);
 	    if (r) {
+                free_expr_tree(sat_node);
 		if (r == E_CANT_TRIG) return OK; else return r;
 	    }
 	} else if (dse == start) {
@@ -1294,13 +1302,18 @@ int DoSatRemind(Trigger *trig, TimeTrig *tt, ParsePtr p)
 	    SaveAllTriggerInfo(trig, tt, dse, tt->ttime, 1);
 	}
 	if (dse == -1) {
+            free_expr_tree(sat_node);
 	    return E_EXPIRED;
 	}
-	s = p->pos;
-	r = EvaluateExpr(p, &v);
-	t = p->pos;
-	if (r) return r;
-	if (v.type != INT_TYPE && v.type != STR_TYPE) return E_BAD_TYPE;
+        r = evaluate_expr_node(sat_node, NULL, &v, &nonconst);
+	if (r) {
+            free_expr_tree(sat_node);
+            return r;
+        }
+	if (v.type != INT_TYPE && v.type != STR_TYPE) {
+            free_expr_tree(sat_node);
+            return E_BAD_TYPE;
+        }
 	if ((v.type == INT_TYPE && v.v.val) ||
 	    (v.type == STR_TYPE && *v.v.str)) {
 	    AdjustTriggerForDuration(trig->scanfrom, dse, trig, tt, 1);
@@ -1325,17 +1338,17 @@ int DoSatRemind(Trigger *trig, TimeTrig *tt, ParsePtr p)
 		}
 		fprintf(ErrFp, "\n");
 	    }
+            free_expr_tree(sat_node);
 	    return OK;
 	}
-	p->pos = s;
 	if (dse+trig->duration_days < start) {
 	    start++;
 	} else {
 	    start = dse+trig->duration_days+1;
 	}
    }
-    p->pos = t;
    LastTrigValid = 0;
+    free_expr_tree(sat_node);
    return E_CANT_TRIG;
 }

--- a/src/dosubst.c
+++ b/src/dosubst.c
@@ -12,6 +12,7 @@
 /***************************************************************/

 #include "config.h"
+#include "types.h"
 #include "expr.h"
 #define L_IN_DOSUBST
 #include <stdio.h>
@@ -20,7 +21,6 @@

 #include <stdlib.h>

-#include "types.h"
 #include "globals.h"
 #include "err.h"
 #include "protos.h"
--- a/src/dynbuf.c
+++ b/src/dynbuf.c
@@ -124,7 +124,9 @@ int DBufPuts(DynamicBuffer *dbuf, char const *str)
 **********************************************************************/
 void DBufFree(DynamicBuffer *dbuf)
 {
-    if (dbuf->buffer != dbuf->staticBuf) free(dbuf->buffer);
+    if (dbuf->buffer != NULL && dbuf->buffer != dbuf->staticBuf) {
+        free(dbuf->buffer);
+    }
    DBufInit(dbuf);
 }

--- a/src/err.h
+++ b/src/err.h
@@ -184,7 +184,7 @@ EXTERN char *ErrMsg[]
    "RUN disabled",
    "Domain error",
    "Invalid identifier",
-    "Recursive function call detected",
+    "Too many recursive function calls",
    "",
    "Cannot modify system variable",
    "C library function can't represent date/time",
--- a/src/expr.c
+++ b/src/expr.c
--- a/src/expr.h
+++ b/src/expr.h
@@ -1,15 +1,19 @@
 /***************************************************************/
 /*                                                             */
-/*  EXPR.H                                                     */
+/*  EXPR_NEW.H                                                 */
 /*                                                             */
-/*  Contains a few definitions used by expression evaluator.   */
+/*  Contains a few definitions used by expression pareser and  */
+/*  evaluator.                                                 */
 /*                                                             */
 /*  This file is part of REMIND.                               */
-/*  Copyright (C) 1992-2024 by Dianne Skoll                    */
-/*  SPDX-License-Identifier: GPL-2.0-only                      */
+/*  Copyright (C) 2022 by Dianne Skoll                         */
 /*                                                             */
 /***************************************************************/

+typedef struct udf_struct UserFunc;
+
+expr_node *parse_expression(char const **e, int *r, Var *locals);
+
 /* Define the types of values */
 #define ERR_TYPE       0
 #define INT_TYPE       1
@@ -20,43 +24,10 @@
 #define SPECIAL_TYPE   6 /* Only for system variables */
 #define CONST_INT_TYPE 7 /* Only for system variables */

-/* Define stuff for parsing expressions */
 #define BEG_OF_EXPR '['
 #define END_OF_EXPR ']'
 #define COMMA ','

-#define UN_OP 0  /* Unary operator */
-#define BIN_OP 1 /* Binary Operator */
-#define FUNC 2   /* Function */
-
-/* Make the pushing and popping of values and operators in-line code
-   for speed.  BEWARE:  These macros invoke return if an error happens ! */
-
-#define PushOpStack(op) \
-    do { if (OpStackPtr >= OP_STACK_SIZE) return E_OP_STK_OVER; \
-        else { OpStack[OpStackPtr++] = (op); if (OpStackPtr > OpStackHiWater) OpStackHiWater = OpStackPtr; } } while(0)
-
-#define PopOpStack(op) \
-if (OpStackPtr <= 0) \
-return E_OP_STK_UNDER; \
-else \
-(op) = OpStack[--OpStackPtr]
-
-#define PushValStack(val) \
-do { if (ValStackPtr >= VAL_STACK_SIZE)  {   \
-    DestroyValue(val); \
-    return E_VA_STK_OVER; \
-} else { \
-    ValStack[ValStackPtr++] = (val); \
-    if (ValStackPtr > ValStackHiWater) ValStackHiWater = ValStackPtr; \
-} } while (0);
-
-#define PopValStack(val) \
-if (ValStackPtr <= 0) \
-return E_VA_STK_UNDER; \
-else \
-(val) = ValStack[--ValStackPtr]
-
 /* These functions are in utils.c and are used to detect overflow
   in various arithmetic operators.  They have to be in separate
   functions with extern linkage to defeat compiler optimizations
@@ -64,4 +35,3 @@ else \
 extern int _private_mul_overflow(int a, int b);
 extern int _private_add_overflow(int a, int b);
 extern int _private_sub_overflow(int a, int b);
-
--- a/src/funcs.c
+++ b/src/funcs.c
@@ -60,6 +60,8 @@
 #define Nargs (info->nargs)
 #define RetVal (info->retval)

+#define DBG(x) do { if (DebugFlag & DB_PRTEXPR) { x; } } while(0)
+
 static int
 solstice_equinox_for_year(int y, int which);

@@ -74,7 +76,7 @@ static int FArgs           (func_info *);
 static int FAsc            (func_info *);
 static int FBaseyr         (func_info *);
 static int FChar           (func_info *);
-static int FChoose         (func_info *);
+static int FChoose         (expr_node *, Value *, Value *, int *);
 static int FCoerce         (func_info *);
 static int FColumns        (func_info *);
 static int FCurrent        (func_info *);
@@ -101,7 +103,7 @@ static int FHebyear        (func_info *);
 static int FHour           (func_info *);
 static int FHtmlEscape     (func_info *);
 static int FHtmlStriptags  (func_info *);
-static int FIif            (func_info *);
+static int FIif            (expr_node *, Value *, Value *, int *);
 static int FIndex          (func_info *);
 static int FIsAny          (func_info *);
 static int FIsdst          (func_info *);
@@ -180,14 +182,9 @@ static int FWkday          (func_info *);
 static int FWkdaynum       (func_info *);
 static int FYear           (func_info *);

-static int CleanUpAfterFunc (func_info *);
-static int CheckArgs       (BuiltinFunc *f, int nargs);
 static int SunStuff        (int rise, double cosz, int dse);
 static int tz_set_tz       (char const *tz);

-/* "Overload" the struct Operator definition */
-#define NO_MAX 127
-
 /* Caches for extracting months, days, years from dates - may
   improve performance slightly. */
 static int CacheDse = -1;
@@ -196,14 +193,9 @@ static int CacheYear, CacheMon, CacheDay;
 static int CacheHebDse = -1;
 static int CacheHebYear, CacheHebMon, CacheHebDay;

-/* We need access to the value stack */
-extern Value ValStack[];
-extern int ValStackPtr;
-extern int ValStackHiWater;
-
 /* Macro for accessing arguments from the value stack - args are numbered
   from 0 to (Nargs - 1) */
-#define ARG(x) (ValStack[ValStackPtr - Nargs + (x)])
+#define ARG(x) (info->args[x])

 #define ARGV(x) ARG(x).v.val
 #define ARGSTR(x) ARG(x).v.str
@@ -231,215 +223,127 @@ extern int ValStackHiWater;

 /* The array holding the built-in functions. */
 BuiltinFunc Func[] = {
-/*	Name		minargs maxargs	is_constant func   */
+/*	Name		minargs maxargs	is_constant func             newfunc*/

-    {   "abs",          1,      1,      1,          FAbs },
-    {   "access",       2,      2,      0,          FAccess },
-    {   "adawn",        0,      1,      0,          FADawn},
-    {   "adusk",        0,      1,      0,          FADusk},
-    {   "ampm",         1,      3,      1,          FAmpm   },
-    {   "ansicolor",    1,      5,      1,          FAnsicolor },
-    {   "args",         1,      1,      0,          FArgs   },
-    {   "asc",          1,      1,      1,          FAsc    },
-    {   "baseyr",       0,      0,      1,          FBaseyr },
-    {   "char",         1,      NO_MAX, 1,          FChar   },
-    {   "choose",       2,      NO_MAX, 1,          FChoose },
-    {   "coerce",       2,      2,      1,          FCoerce },
-    {   "columns",      0,      1,      0,          FColumns },
-    {   "current",      0,      0,      0,          FCurrent },
-    {   "date",         3,      3,      1,          FDate   },
-    {   "datepart",     1,      1,      1,          FDatepart },
-    {   "datetime",     2,      5,      1,          FDateTime },
-    {   "dawn",         0,      1,      0,          FDawn},
-    {   "day",          1,      1,      1,          FDay    },
-    {   "daysinmon",    2,      2,      1,          FDaysinmon },
-    {   "defined",      1,      1,      0,          FDefined },
-    {   "dosubst",      1,      3,      0,          FDosubst },
-    {   "dusk",         0,      1,      0,          FDusk },
-    {   "easterdate",   0,      1,      0,          FEasterdate },
-    {   "evaltrig",     1,      2,      0,          FEvalTrig },
-    {   "filedate",     1,      1,      0,          FFiledate },
-    {   "filedatetime", 1,      1,      0,          FFiledatetime },
-    {   "filedir",      0,      0,      0,          FFiledir },
-    {   "filename",     0,      0,      0,          FFilename },
-    {   "getenv",       1,      1,      0,          FGetenv },
-    {   "hebdate",      2,      5,      0,          FHebdate },
-    {   "hebday",       1,      1,      0,          FHebday },
-    {   "hebmon",       1,      1,      0,          FHebmon },
-    {   "hebyear",      1,      1,      0,          FHebyear },
-    {   "hour",         1,      1,      1,          FHour   },
-    {   "htmlescape",   1,      1,      1,          FHtmlEscape },
-    {   "htmlstriptags",1,      1,      1,          FHtmlStriptags },
-    {   "iif",          1,      NO_MAX, 1,          FIif    },
-    {   "index",        2,      3,      1,          FIndex  },
-    {   "isany",        1,      NO_MAX, 1,          FIsAny  },
-    {   "isdst",        0,      2,      0,          FIsdst },
-    {   "isleap",       1,      1,      1,          FIsleap },
-    {   "isomitted",    1,      1,      0,          FIsomitted },
-    {   "language",     0,      0,      1,          FLanguage },
-    {   "localtoutc",   1,      1,      1,          FLocalToUTC },
-    {   "lower",        1,      1,      1,          FLower  },
-    {   "max",          1,      NO_MAX, 1,          FMax    },
-    {   "min",          1,      NO_MAX, 1,          FMin    },
-    {   "minsfromutc",  0,      2,      0,          FMinsfromutc },
-    {   "minute",       1,      1,      1,          FMinute },
-    {   "mon",          1,      1,      1,          FMon    },
-    {   "monnum",       1,      1,      1,          FMonnum },
-    {   "moondate",     1,      3,      0,          FMoondate },
-    {   "moondatetime", 1,      3,      0,          FMoondatetime },
-    {   "moonphase",    0,      2,      0,          FMoonphase },
-    {   "moontime",     1,      3,      0,          FMoontime },
-    {   "multitrig",    1,      NO_MAX, 0,          FMultiTrig },
-    {   "ndawn",        0,      1,      0,          FNDawn},
-    {   "ndusk",        0,      1,      0,          FNDusk},
-    {   "nonomitted",   2,      NO_MAX, 0,          FNonomitted },
-    {   "now",          0,      0,      0,          FNow    },
-    {   "ord",          1,      1,      1,          FOrd    },
-    {   "orthodoxeaster",0,     1,      0,          FOrthodoxeaster },
-    {   "ostype",       0,      0,      1,          FOstype },
-    {   "pad",          3,      4,      1,          FPad    },
-    {   "plural",       1,      3,      1,          FPlural },
-    {   "psmoon",       1,      4,      1,          FPsmoon},
-    {   "psshade",      1,      3,      1,          FPsshade},
-    {   "realcurrent",  0,      0,      0,          FRealCurrent},
-    {   "realnow",      0,      0,      0,          FRealnow},
-    {   "realtoday",    0,      0,      0,          FRealtoday },
-    {   "rows",         0,      0,      0,          FRows },
-    {   "sgn",          1,      1,      1,          FSgn    },
-    {   "shell",        1,      2,      0,          FShell  },
-    {   "shellescape",  1,      1,      1,          FShellescape },
-    {   "slide",        2,      NO_MAX, 0,          FSlide  },
-    {   "soleq",        1,      2,      0,          FSoleq  },
-    {   "stdout",       0,      0,      1,          FStdout },
-    {   "strlen",       1,      1,      1,          FStrlen },
-    {   "substr",       2,      3,      1,          FSubstr },
-    {   "sunrise",      0,      1,      0,          FSunrise},
-    {   "sunset",       0,      1,      0,          FSunset },
-    {   "time",         2,      2,      1,          FTime   },
-    {   "timepart",     1,      1,      1,          FTimepart },
-    {   "timezone",     0,      1,      1,          FTimezone },
-    {   "today",        0,      0,      0,          FToday  },
-    {   "trig",         0,      NO_MAX, 0,          FTrig },
-    {   "trigback",     0,      0,      0,          FTrigback },
-    {   "trigdate",     0,      0,      0,          FTrigdate },
-    {   "trigdatetime", 0,      0,      0,          FTrigdatetime },
-    {   "trigdelta",    0,      0,      0,          FTrigdelta },
-    {   "trigduration", 0,      0,      0,          FTrigduration },
-    {   "trigeventduration", 0, 0,      0,          FTrigeventduration },
-    {   "trigeventstart", 0,    0,      0,          FTrigeventstart },
-    {   "trigfrom",     0,      0,      0,          FTrigfrom },
-    {   "trigger",      1,      3,      0,          FTrigger },
-    {   "trigpriority", 0,      0,      0,          FTrigpriority },
-    {   "trigrep",      0,      0,      0,          FTrigrep },
-    {   "trigscanfrom", 0,      0,      0,          FTrigscanfrom },
-    {   "trigtags",     0,      0,      0,          FTrigtags },
-    {   "trigtime",     0,      0,      0,          FTrigtime },
-    {   "trigtimedelta",0,      0,      0,          FTrigtimedelta },
-    {   "trigtimerep",  0,      0,      0,          FTrigtimerep },
-    {   "triguntil",    0,      0,      0,          FTriguntil },
-    {   "trigvalid",    0,      0,      0,          FTrigvalid },
-    {   "typeof",       1,      1,      1,          FTypeof },
-    {   "tzconvert",    2,      3,      0,          FTzconvert },
-    {   "upper",        1,      1,      1,          FUpper  },
-    {   "utctolocal",   1,      1,      1,          FUTCToLocal },
-    {   "value",        1,      2,      0,          FValue  },
-    {   "version",      0,      0,      1,          FVersion },
-    {   "weekno",       0,      3,      1,          FWeekno },
-    {   "wkday",        1,      1,      1,          FWkday  },
-    {   "wkdaynum",     1,      1,      1,          FWkdaynum },
-    {   "year",         1,      1,      1,          FYear   }
+    {   "abs",          1,      1,      1,          FAbs, NULL },
+    {   "access",       2,      2,      0,          FAccess, NULL },
+    {   "adawn",        0,      1,      0,          FADawn, NULL},
+    {   "adusk",        0,      1,      0,          FADusk, NULL},
+    {   "ampm",         1,      3,      1,          FAmpm, NULL },
+    {   "ansicolor",    1,      5,      1,          FAnsicolor, NULL },
+    {   "args",         1,      1,      0,          FArgs, NULL },
+    {   "asc",          1,      1,      1,          FAsc, NULL },
+    {   "baseyr",       0,      0,      1,          FBaseyr, NULL },
+    {   "char",         1,      NO_MAX, 1,          FChar, NULL },
+    {   "choose",       2,      NO_MAX, 1,          NULL, FChoose }, /*NEW-STYLE*/
+    {   "coerce",       2,      2,      1,          FCoerce, NULL },
+    {   "columns",      0,      1,      0,          FColumns, NULL },
+    {   "current",      0,      0,      0,          FCurrent, NULL },
+    {   "date",         3,      3,      1,          FDate, NULL },
+    {   "datepart",     1,      1,      1,          FDatepart, NULL },
+    {   "datetime",     2,      5,      1,          FDateTime, NULL },
+    {   "dawn",         0,      1,      0,          FDawn, NULL },
+    {   "day",          1,      1,      1,          FDay, NULL },
+    {   "daysinmon",    2,      2,      1,          FDaysinmon, NULL },
+    {   "defined",      1,      1,      0,          FDefined, NULL },
+    {   "dosubst",      1,      3,      0,          FDosubst, NULL },
+    {   "dusk",         0,      1,      0,          FDusk, NULL },
+    {   "easterdate",   0,      1,      0,          FEasterdate, NULL },
+    {   "evaltrig",     1,      2,      0,          FEvalTrig, NULL },
+    {   "filedate",     1,      1,      0,          FFiledate, NULL },
+    {   "filedatetime", 1,      1,      0,          FFiledatetime, NULL },
+    {   "filedir",      0,      0,      0,          FFiledir, NULL },
+    {   "filename",     0,      0,      0,          FFilename, NULL },
+    {   "getenv",       1,      1,      0,          FGetenv, NULL },
+    {   "hebdate",      2,      5,      0,          FHebdate, NULL },
+    {   "hebday",       1,      1,      0,          FHebday, NULL },
+    {   "hebmon",       1,      1,      0,          FHebmon, NULL },
+    {   "hebyear",      1,      1,      0,          FHebyear, NULL },
+    {   "hour",         1,      1,      1,          FHour, NULL },
+    {   "htmlescape",   1,      1,      1,          FHtmlEscape, NULL },
+    {   "htmlstriptags",1,      1,      1,          FHtmlStriptags, NULL },
+    {   "iif",          1,      NO_MAX, 1,          NULL, FIif }, /*NEW-STYLE*/
+    {   "index",        2,      3,      1,          FIndex, NULL },
+    {   "isany",        1,      NO_MAX, 1,          FIsAny, NULL },
+    {   "isdst",        0,      2,      0,          FIsdst, NULL },
+    {   "isleap",       1,      1,      1,          FIsleap, NULL },
+    {   "isomitted",    1,      1,      0,          FIsomitted, NULL },
+    {   "language",     0,      0,      1,          FLanguage, NULL },
+    {   "localtoutc",   1,      1,      1,          FLocalToUTC, NULL },
+    {   "lower",        1,      1,      1,          FLower, NULL },
+    {   "max",          1,      NO_MAX, 1,          FMax, NULL },
+    {   "min",          1,      NO_MAX, 1,          FMin, NULL },
+    {   "minsfromutc",  0,      2,      0,          FMinsfromutc, NULL },
+    {   "minute",       1,      1,      1,          FMinute, NULL },
+    {   "mon",          1,      1,      1,          FMon, NULL },
+    {   "monnum",       1,      1,      1,          FMonnum, NULL },
+    {   "moondate",     1,      3,      0,          FMoondate, NULL },
+    {   "moondatetime", 1,      3,      0,          FMoondatetime, NULL },
+    {   "moonphase",    0,      2,      0,          FMoonphase, NULL },
+    {   "moontime",     1,      3,      0,          FMoontime, NULL },
+    {   "multitrig",    1,      NO_MAX, 0,          FMultiTrig, NULL },
+    {   "ndawn",        0,      1,      0,          FNDawn, NULL },
+    {   "ndusk",        0,      1,      0,          FNDusk, NULL },
+    {   "nonomitted",   2,      NO_MAX, 0,          FNonomitted, NULL },
+    {   "now",          0,      0,      0,          FNow, NULL },
+    {   "ord",          1,      1,      1,          FOrd, NULL },
+    {   "orthodoxeaster",0,     1,      0,          FOrthodoxeaster, NULL },
+    {   "ostype",       0,      0,      1,          FOstype, NULL },
+    {   "pad",          3,      4,      1,          FPad, NULL },
+    {   "plural",       1,      3,      1,          FPlural, NULL },
+    {   "psmoon",       1,      4,      1,          FPsmoon, NULL },
+    {   "psshade",      1,      3,      1,          FPsshade, NULL },
+    {   "realcurrent",  0,      0,      0,          FRealCurrent, NULL },
+    {   "realnow",      0,      0,      0,          FRealnow, NULL },
+    {   "realtoday",    0,      0,      0,          FRealtoday, NULL },
+    {   "rows",         0,      0,      0,          FRows, NULL },
+    {   "sgn",          1,      1,      1,          FSgn, NULL },
+    {   "shell",        1,      2,      0,          FShell, NULL },
+    {   "shellescape",  1,      1,      1,          FShellescape, NULL },
+    {   "slide",        2,      NO_MAX, 0,          FSlide, NULL },
+    {   "soleq",        1,      2,      0,          FSoleq, NULL },
+    {   "stdout",       0,      0,      1,          FStdout, NULL },
+    {   "strlen",       1,      1,      1,          FStrlen, NULL },
+    {   "substr",       2,      3,      1,          FSubstr, NULL },
+    {   "sunrise",      0,      1,      0,          FSunrise, NULL },
+    {   "sunset",       0,      1,      0,          FSunset, NULL },
+    {   "time",         2,      2,      1,          FTime, NULL },
+    {   "timepart",     1,      1,      1,          FTimepart, NULL },
+    {   "timezone",     0,      1,      1,          FTimezone, NULL },
+    {   "today",        0,      0,      0,          FToday, NULL },
+    {   "trig",         0,      NO_MAX, 0,          FTrig, NULL },
+    {   "trigback",     0,      0,      0,          FTrigback, NULL },
+    {   "trigdate",     0,      0,      0,          FTrigdate, NULL },
+    {   "trigdatetime", 0,      0,      0,          FTrigdatetime, NULL },
+    {   "trigdelta",    0,      0,      0,          FTrigdelta, NULL },
+    {   "trigduration", 0,      0,      0,          FTrigduration, NULL },
+    {   "trigeventduration", 0, 0,      0,          FTrigeventduration, NULL },
+    {   "trigeventstart", 0,    0,      0,          FTrigeventstart, NULL },
+    {   "trigfrom",     0,      0,      0,          FTrigfrom, NULL },
+    {   "trigger",      1,      3,      0,          FTrigger, NULL },
+    {   "trigpriority", 0,      0,      0,          FTrigpriority, NULL },
+    {   "trigrep",      0,      0,      0,          FTrigrep, NULL },
+    {   "trigscanfrom", 0,      0,      0,          FTrigscanfrom, NULL },
+    {   "trigtags",     0,      0,      0,          FTrigtags, NULL },
+    {   "trigtime",     0,      0,      0,          FTrigtime, NULL },
+    {   "trigtimedelta",0,      0,      0,          FTrigtimedelta, NULL },
+    {   "trigtimerep",  0,      0,      0,          FTrigtimerep, NULL },
+    {   "triguntil",    0,      0,      0,          FTriguntil, NULL },
+    {   "trigvalid",    0,      0,      0,          FTrigvalid, NULL },
+    {   "typeof",       1,      1,      1,          FTypeof, NULL },
+    {   "tzconvert",    2,      3,      0,          FTzconvert, NULL },
+    {   "upper",        1,      1,      1,          FUpper, NULL },
+    {   "utctolocal",   1,      1,      1,          FUTCToLocal, NULL },
+    {   "value",        1,      2,      0,          FValue, NULL },
+    {   "version",      0,      0,      1,          FVersion, NULL },
+    {   "weekno",       0,      3,      1,          FWeekno, NULL },
+    {   "wkday",        1,      1,      1,          FWkday, NULL },
+    {   "wkdaynum",     1,      1,      1,          FWkdaynum, NULL },
+    {   "year",         1,      1,      1,          FYear, NULL }
 };

 /* Need a variable here - Func[] array not really visible to outside. */
-int NumFuncs = sizeof(Func) / sizeof(Operator) ;
-
-/***************************************************************/
-/*                                                             */
-/*  CallFunc                                                   */
-/*                                                             */
-/*  Call a function given a pointer to it, and the number      */
-/*  of arguments supplied.                                     */
-/*                                                             */
-/***************************************************************/
-int CallFunc(BuiltinFunc *f, int nargs)
-{
-    register int r = CheckArgs(f, nargs);
-    int i;
-
-    func_info info_obj;
-    func_info *info = &info_obj;
-
-    Nargs = nargs;
-    RetVal.type = ERR_TYPE;
-
-    if (DebugFlag & DB_PRTEXPR) {
-	fprintf(ErrFp, "%s(", f->name);
-	for (i=0; i<nargs; i++) {
-	    PrintValue(&ARG(i), ErrFp);
-	    if (i<nargs-1) fprintf(ErrFp, ", ");
-	}
-	fprintf(ErrFp, ") => ");
-	if (r) {
-	    fprintf(ErrFp, "%s\n", ErrMsg[r]);
-	    return r;
-	}
-    }
-    if (r) {
-	Eprint("%s(): %s", f->name, ErrMsg[r]);
-	return r;
-    }
-
-    r = (*(f->func))(info);
-    if (r) {
-	DestroyValue(RetVal);
-	if (DebugFlag & DB_PRTEXPR)
-	    fprintf(ErrFp, "%s\n", ErrMsg[r]);
-	else
-	    Eprint("%s(): %s", f->name, ErrMsg[r]);
-	return r;
-    }
-    if (DebugFlag & DB_PRTEXPR) {
-	PrintValue(&RetVal, ErrFp);
-	fprintf(ErrFp, "\n");
-    }
-    r = CleanUpAfterFunc(info);
-    return r;
-}
-
-/***************************************************************/
-/*                                                             */
-/*  CheckArgs                                                  */
-/*                                                             */
-/*  Check that the right number of args have been supplied     */
-/*  for a function.                                            */
-/*                                                             */
-/***************************************************************/
-static int CheckArgs(BuiltinFunc *f, int nargs)
-{
-    if (nargs < f->minargs) return E_2FEW_ARGS;
-    if (nargs > f->maxargs && f->maxargs != NO_MAX) return E_2MANY_ARGS;
-    return OK;
-}
-/***************************************************************/
-/*                                                             */
-/*  CleanUpAfterFunc                                           */
-/*                                                             */
-/*  Clean up the stack after a function call - remove          */
-/*  args and push the new value.                               */
-/*                                                             */
-/***************************************************************/
-static int CleanUpAfterFunc(func_info *info)
-{
-    Value v;
-    int i;
-
-    for (i=0; i<Nargs; i++) {
-	PopValStack(v);
-	DestroyValue(v);
-    }
-    PushValStack(RetVal);
-    return OK;
-}
+int NumFuncs = sizeof(Func) / sizeof(BuiltinFunc) ;

 /***************************************************************/
 /*                                                             */
@@ -1279,6 +1183,9 @@ static int FIsAny(func_info *info)
    return OK;
 }

+/* Debugging helpers for "choose()" and "iif() */
+#define PUT(x) DBufPuts(&DebugBuf, x)
+#define OUT() do { fprintf(ErrFp, "%s\n", DBufValue(&DebugBuf)); DBufFree(&DebugBuf); } while(0)
 /***************************************************************/
 /*                                                             */
 /*  FChoose                                                    */
@@ -1287,15 +1194,63 @@ static int FIsAny(func_info *info)
 /*  from 1.                                                    */
 /*                                                             */
 /***************************************************************/
-static int FChoose(func_info *info)
+static int FChoose(expr_node *node, Value *locals, Value *ans, int *nonconst)
 {
-    int v;
+    DynamicBuffer DebugBuf;
+    expr_node *cur;
+    int r;
+    int n;
+    int nargs = node->num_kids;
+    Value(v);
+    DBG(DBufInit(&DebugBuf));
+    PUT("choose(");

-    ASSERT_TYPE(0, INT_TYPE);
-    v = ARGV(0);
-    if (v < 1) v = 1;
-    if (v > Nargs-1) v = Nargs-1;
-    DCOPYVAL(RetVal, ARG(v));
+    cur = node->child;
+    r = evaluate_expr_node(cur, locals, &v, nonconst);
+    if (r != OK) {
+        DBG(DBufFree(&DebugBuf));
+        return r;
+    }
+    DBG(PUT(PrintValue(&v, NULL)));
+    if (v.type != INT_TYPE) {
+        if (DebugFlag & DB_PRTEXPR) {
+            cur = cur->sibling;
+            while(cur) {
+                PUT(", ?");
+                cur = cur->sibling;
+            }
+            PUT(") => ");
+            PUT(ErrMsg[E_BAD_TYPE]);
+            OUT();
+        }
+        return E_BAD_TYPE;
+    }
+    n = v.v.val;
+    if (n < 1) n = 1;
+    if (n > nargs-1) n = nargs-1;
+
+    while(n--) {
+        cur = cur->sibling;
+        DBG(if (n) { PUT(", ?"); });
+        if (!cur) return E_SWERR; /* Should not happen! */
+    }
+    r = evaluate_expr_node(cur, locals, ans, nonconst);
+    if (r != OK) {
+        DBG(DBufFree(&DebugBuf));
+        return r;
+    }
+    if (DebugFlag & DB_PRTEXPR) {
+        PUT(", ");
+        PUT(PrintValue(ans, NULL));
+        cur = cur->sibling;
+        while(cur) {
+            PUT(", ?");
+            cur = cur->sibling;
+        }
+        PUT(") => ");
+        PUT(PrintValue(ans, NULL));
+        OUT();
+    }
    return OK;
 }

@@ -1481,7 +1436,7 @@ static int FValue(func_info *info)
    ASSERT_TYPE(0, STR_TYPE);
    switch(Nargs) {
    case 1:
-	return GetVarValue(ARGSTR(0), &RetVal, NULL, NULL);
+	return GetVarValue(ARGSTR(0), &RetVal);

    case 2:
 	v = FindVar(ARGSTR(0), 0);
@@ -1953,33 +1908,101 @@ static int FIndex(func_info *info)
 /*                                                             */
 /*  FIif                                                       */
 /*                                                             */
-/*  The IIF function.                                          */
+/*  The IIF function.  Uses new-style evaluation               */
 /*                                                             */
 /***************************************************************/
-static int FIif(func_info *info)
+static int FIif(expr_node *node, Value *locals, Value *ans, int *nonconst)
 {
    int istrue;
-    int arg;
+    int r;
+    int done;
+    Value v;
+    expr_node *cur;
+    DynamicBuffer DebugBuf;

-    if (!(Nargs % 2)) return E_IIF_ODD;
+    DBG(DBufInit(&DebugBuf));
+    DBG(PUT("iif("));
+    cur = node->child;

-    for (arg=0; arg<Nargs-1; arg += 2) {
-	if (ARG(arg).type != STR_TYPE && ARG(arg).type != INT_TYPE)
-	    return E_BAD_TYPE;
-
-	if (ARG(arg).type == INT_TYPE)
-	    istrue = ARG(arg).v.val;
-	else
-	    istrue = *(ARG(arg).v.str);
-
-	if (istrue) {
-	    DCOPYVAL(RetVal, ARG(arg+1));
-	    return OK;
-	}
+    if (!(node->num_kids % 2)) {
+        if (DebugFlag & DB_PRTEXPR) {
+            r = 0;
+            while(cur) {
+                if (r) PUT(", ");
+                r=1;
+                PUT("?");
+                cur = cur->sibling;
+            }
+            PUT(") => ");
+            PUT(ErrMsg[E_IIF_ODD]);
+            OUT();
+        }
+        return E_IIF_ODD;
    }

-    DCOPYVAL(RetVal, ARG(Nargs-1));
-    return OK;
+
+    done = 0;
+    while(cur->sibling) {
+        r = evaluate_expr_node(cur, locals, &v, nonconst);
+        if (r != OK) {
+            DBG(DBufFree(&DebugBuf));
+            return r;
+        }
+        if (DebugFlag & DB_PRTEXPR) {
+            if (done) PUT(", ");
+            done = 1;
+            PUT(PrintValue(&v, NULL));
+        }
+	if (v.type != STR_TYPE && v.type != INT_TYPE) {
+            if (DebugFlag & DB_PRTEXPR) {
+                cur = cur->sibling;
+                while(cur) {
+                    PUT(", ?");
+                    cur = cur->sibling;
+                }
+                PUT(") => ");
+                PUT(ErrMsg[E_BAD_TYPE]);
+                OUT();
+            }
+	    return E_BAD_TYPE;
+        }
+
+	if (v.type == INT_TYPE) {
+	    istrue = v.v.val;
+        } else {
+	    istrue = *(v.v.str);
+        }
+	if (istrue) {
+            r = evaluate_expr_node(cur->sibling, locals, ans, nonconst);
+            if (r == OK && (DebugFlag & DB_PRTEXPR)) {
+                PUT(", ");
+                PUT(PrintValue(ans, NULL));
+                cur = cur->sibling->sibling;
+                while(cur) {
+                    PUT(", ?");
+                    cur = cur->sibling;
+                }
+                PUT(") => ");
+                PUT(PrintValue(ans, NULL));
+                OUT();
+            }
+            DBG(DBufFree(&DebugBuf));
+            return r;
+	}
+        DBG(PUT(", ?"));
+        cur = cur->sibling->sibling;
+    }
+
+    /* Return the last arg */
+    r = evaluate_expr_node(cur, locals, ans, nonconst);
+    if (DebugFlag & DB_PRTEXPR) {
+        if (done) PUT(", ");
+        PUT(PrintValue(ans, NULL));
+        PUT(") => ");
+        PUT(PrintValue(ans, NULL));
+        OUT();
+    }
+    return r;
 }

 /***************************************************************/
@@ -2373,14 +2396,18 @@ static int FEasterdate(func_info *info)
 {
    int y, m, d;
    int g, c, x, z, e, n;
+    int base;
    if (Nargs == 0) {
+        base = DSEToday;
        FromDSE(DSEToday, &y, &m, &d);
    } else {
        if (ARG(0).type == INT_TYPE) {
+            base = -1;
            y = ARGV(0);
            if (y < BASE) return E_2LOW;
            else if (y > BASE+YR_RANGE) return E_2HIGH;
        } else if (HASDATE(ARG(0))) {
+            base = DATEPART(ARG(0));
            FromDSE(DATEPART(ARG(0)), &y, &m, &d);  /* We just want the year */
        } else return E_BAD_TYPE;
    }
@@ -2406,7 +2433,7 @@ static int FEasterdate(func_info *info)

 	RetVal.type = DATE_TYPE;
 	RETVAL = DSE(y, m, d);
-	y++; } while (HASDATE(ARG(0)) && RETVAL < DATEPART(ARG(0)));
+	y++; } while (base > -1 && RETVAL < base);

    return OK;
 }
@@ -2422,7 +2449,9 @@ static int FOrthodoxeaster(func_info *info)
 {
    int y, m, d;
    int a, b, c, dd, e, f, dse;
+    int base = -1;
    if (Nargs == 0) {
+        base = DSEToday;
        FromDSE(DSEToday, &y, &m, &d);
    } else {
        if (ARG(0).type == INT_TYPE) {
@@ -2430,6 +2459,7 @@ static int FOrthodoxeaster(func_info *info)
            if (y < BASE) return E_2LOW;
            else if (y > BASE+YR_RANGE) return E_2HIGH;
        } else if (HASDATE(ARG(0))) {
+            base = DATEPART(ARG(0));
            FromDSE(DATEPART(ARG(0)), &y, &m, &d);  /* We just want the year */
        } else return E_BAD_TYPE;
    }
@@ -2449,7 +2479,7 @@ static int FOrthodoxeaster(func_info *info)
 	RetVal.type = DATE_TYPE;
 	RETVAL = dse;
 	y++;
-    } while (HASDATE(ARG(0)) && RETVAL < DATEPART(ARG(0)));
+    } while (base > -1 && RETVAL < base);

    return OK;
 }
@@ -3896,3 +3926,38 @@ FSoleq(func_info *info)
    RETVAL = ret;
    return OK;
 }
+
+/* Compare two strings case-insensitively, where we KNOW
+   that the second string is definitely lower-case */
+static int strcmp_lcfirst(char const *s1, char const *s2)
+{
+    int r;
+    while (*s1 && *s2) {
+	r = tolower(*s1) - *s2;
+	if (r) return r;
+	s1++;
+	s2++;
+    }
+    return tolower(*s1) - *s2;
+}
+
+/***************************************************************/
+/*                                                             */
+/*  FindBuiltinFunc                                            */
+/*                                                             */
+/*  Find a built-in function.                                  */
+/*                                                             */
+/***************************************************************/
+BuiltinFunc *FindBuiltinFunc(char const *name)
+{
+    int top=NumFuncs-1, bot=0;
+    int mid, r;
+    while (top >= bot) {
+	mid = (top + bot) / 2;
+	r = strcmp_lcfirst(name, Func[mid].name);
+	if (!r) return &Func[mid];
+	else if (r > 0) bot = mid+1;
+	else top = mid-1;
+    }
+    return NULL;
+}
--- a/src/globals.h
+++ b/src/globals.h
@@ -159,6 +159,9 @@ EXTERN DynamicBuffer Banner;
 EXTERN DynamicBuffer LineBuffer;
 EXTERN DynamicBuffer ExprBuf;

+/* User-func recursion level */
+EXTERN  INIT(   unsigned int FuncRecursionLevel, 0);
+
 extern int NumFullOmits, NumPartialOmits;

 /* List of months */
--- a/src/init.c
+++ b/src/init.c
@@ -605,7 +605,7 @@ void InitRemind(int argc, char const *argv[])
 	    case 'D':
 		while (*arg) {
 		    switch(*arg++) {
-                    case 's': case 'S': DebugFlag |= DB_EXPR_STACKS; break;
+                    case 's': case 'S': DebugFlag |= DB_PARSE_EXPR;  break;
 		    case 'e': case 'E': DebugFlag |= DB_ECHO_LINE;   break;
 		    case 'x': case 'X': DebugFlag |= DB_PRTEXPR;     break;
 		    case 't': case 'T': DebugFlag |= DB_PRTTRIG;     break;
--- a/src/langs/finnish.h
+++ b/src/langs/finnish.h
@@ -246,7 +246,9 @@ EXTERN char *ErrMsg[] =
    "String too long",
    "Time specified twice",
    "Cannot specify DURATION without specifying AT",
-    "Odotettu viikonpäivän nimi"
+    "Odotettu viikonpäivän nimi",
+    "Päällekkäinen argumentin nimi"
+
 };
 #endif /* MK_GLOBALS */

--- a/src/langs/french.h
+++ b/src/langs/french.h
@@ -221,6 +221,7 @@ EXTERN char *ErrMsg[] =
    "Time specified twice",
    "Cannot specify DURATION without specifying AT",
    "Nom du jour de la semaine attendu",
+    "Nom de l'argument en double",
 };
 #endif /* MK_GLOBALS */

--- a/src/langs/polish.h
+++ b/src/langs/polish.h
@@ -236,7 +236,8 @@ EXTERN char *ErrMsg[] =
    "String too long",
    "Time specified twice",
    "Cannot specify DURATION without specifying AT",
-    "Oczekiwana nazwa dnia tygodnia"
+    "Oczekiwana nazwa dnia tygodnia",
+    "Zduplikowana nazwa argumentu",
 };
 #endif /* MK_GLOBALS */

--- a/src/langs/portbr.h
+++ b/src/langs/portbr.h
@@ -246,6 +246,7 @@ EXTERN char *ErrMsg[] =
    "Time specified twice",
    "Cannot specify DURATION without specifying AT",
    "Esperando nome do dia da semana",
+    "Nome de argumento duplicado"
 };
 #endif /* MK_GLOBALS */

--- a/src/main.c
+++ b/src/main.c
@@ -55,6 +55,15 @@ static void DoReminders(void);
 /* Macro for simplifying common block so as not to litter code */
 #define OUTPUT(c) do { if (output) { DBufPutc(output, c); } else { putchar(c); } } while(0)

+void
+exitfunc(void)
+{
+    if (DebugFlag & DB_PARSE_EXPR) {
+        UnsetAllUserFuncs();
+        print_expr_nodes_stats();
+    }
+}
+
 /***************************************************************/
 /***************************************************************/
 /**                                                           **/
@@ -81,7 +90,7 @@ int main(int argc, char *argv[])
    DBufInit(&(LastTrigger.tags));
    ClearLastTriggers();

-    atexit(DebugExitFunc);
+    atexit(exitfunc);

    if (DoCalendar || (DoSimpleCalendar && (!NextMode || PsCal))) {
 	ProduceCalendar();
@@ -289,6 +298,7 @@ static void DoReminders(void)
 	    case T_RemType: if (tok.val == RUN_TYPE) {
 		    r=DoRun(&p);
 		} else {
+		    DestroyParser(&p);
 		    CreateParser(CurLine, &p);
 		    r=DoRem(&p);
 		    purge_handled = 1;
@@ -297,10 +307,8 @@ static void DoReminders(void)


 	    /* If we don't recognize the command, do a REM by default */
-	    /* Note:  Since the parser hasn't been used yet, we don't */
-	    /* need to destroy it here. */

-	    default: CreateParser(CurLine, &p); purge_handled = 1; r=DoRem(&p); break;
+	    default: DestroyParser(&p); CreateParser(CurLine, &p); purge_handled = 1; r=DoRem(&p); break;

 	    }
 	    if (r && (!Hush || r != E_RUN_DISABLED)) {
@@ -582,6 +590,53 @@ int ParseIdentifier(ParsePtr p, DynamicBuffer *dbuf)
    }
 }

+/***************************************************************/
+/*                                                             */
+/* ParseExpr                                                   */
+/*                                                             */
+/* We are expecting an expression here.  Parse it and return   */
+/* the value node tree.                                        */
+/*                                                             */
+/***************************************************************/
+expr_node * ParseExpr(ParsePtr p, int *r)
+{
+
+    int bracketed = 0;
+    expr_node *node;
+
+    if (p->isnested) {
+        *r = E_PARSE_ERR;  /* Can't nest expressions */
+        return NULL;
+    }
+    if (!p->pos) {
+        *r = E_PARSE_ERR;      /* Missing expression */
+        return NULL;
+    }
+
+    while (isempty(*p->pos)) (p->pos)++;
+    if (!*(p->pos)) {
+        *r = E_EOLN;
+        return NULL;
+    }
+    if (*p->pos == BEG_OF_EXPR) {
+	(p->pos)++;
+	bracketed = 1;
+    }
+    node = parse_expression(&(p->pos), r, NULL);
+    if (*r) {
+        return free_expr_tree(node);
+    }
+
+    if (bracketed) {
+	if (*p->pos != END_OF_EXPR) {
+            *r = E_MISS_END;
+            return free_expr_tree(node);
+        }
+	(p->pos)++;
+    }
+    return node;
+}
+
 /***************************************************************/
 /*                                                             */
 /* EvaluateExpr                                                */
@@ -593,21 +648,22 @@ int ParseIdentifier(ParsePtr p, DynamicBuffer *dbuf)
 int EvaluateExpr(ParsePtr p, Value *v)
 {

-    int bracketed = 0;
    int r;
+    int nonconst = 0;
+    expr_node *node = ParseExpr(p, &r);

-    if (p->isnested) return E_PARSE_ERR;  /* Can't nest expressions */
-    if (!p->pos) return E_PARSE_ERR;      /* Missing expression */
-    while (isempty(*p->pos)) (p->pos)++;
-    if (*p->pos == BEG_OF_EXPR) {
-	(p->pos)++;
-	bracketed = 1;
+    if (r != OK) {
+        return r;
    }
-    r = EvalExpr(&(p->pos), v, p);
+    if (!node) {
+        return E_SWERR;
+    }
+
+    r = evaluate_expr_node(node, NULL, v, &nonconst);
+    free_expr_tree(node);
    if (r) return r;
-    if (bracketed) {
-	if (*p->pos != END_OF_EXPR) return E_MISS_END;
-	(p->pos)++;
+    if (nonconst) {
+        p->nonconst_expr = 1;
    }
    return OK;
 }
@@ -651,27 +707,34 @@ void Eprint(char const *fmt, ...)
 	FreshLine = 0;
 	if (strcmp(FileName, "-")) {
 	    (void) fprintf(ErrFp, "%s(%d): ", FileName, LineNo);
+            va_start(argptr, fmt);
+            (void) vfprintf(ErrFp, fmt, argptr);
+            (void) fputc('\n', ErrFp);
+            va_end(argptr);
            if (print_callstack(ErrFp)) {
-                (void) fprintf(ErrFp, ": ");
+                (void) fprintf(ErrFp, "\n");
            }
        } else {
 	    (void) fprintf(ErrFp, "-stdin-(%d): ", LineNo);
+            va_start(argptr, fmt);
+            (void) vfprintf(ErrFp, fmt, argptr);
+            (void) fputc('\n', ErrFp);
+            va_end(argptr);
            if (print_callstack(ErrFp)) {
-                (void) fprintf(ErrFp, ": ");
+                (void) fprintf(ErrFp, "\n");
            }
        }
 	if (DebugFlag & DB_PRTLINE) OutputLine(ErrFp);
    } else if (FileName) {
 	fprintf(ErrFp, "       ");
+        va_start(argptr, fmt);
+        (void) vfprintf(ErrFp, fmt, argptr);
+        (void) fputc('\n', ErrFp);
+        va_end(argptr);
        if (print_callstack(ErrFp)) {
-            (void) fprintf(ErrFp, ": ");
+            (void) fprintf(ErrFp, "\n");
        }
    }
-
-    va_start(argptr, fmt);
-    (void) vfprintf(ErrFp, fmt, argptr);
-    (void) fputc('\n', ErrFp);
-    va_end(argptr);
    return;
 }

@@ -1025,8 +1088,8 @@ int DoDebug(ParsePtr p)

        case 's':
        case 'S':
-	    if (val) DebugFlag |=  DB_EXPR_STACKS;
-	    else     DebugFlag &= ~DB_EXPR_STACKS;
+	    if (val) DebugFlag |=  DB_PARSE_EXPR;
+	    else     DebugFlag &= ~DB_PARSE_EXPR;
 	    break;

 	case 'x':
--- a/src/protos.h
+++ b/src/protos.h
@@ -43,6 +43,7 @@
 int CallUserFunc (char const *name, int nargs, ParsePtr p);
 int DoFset (ParsePtr p);
 int DoFunset (ParsePtr p);
+void UnsetAllUserFuncs(void);
 void ProduceCalendar (void);
 char const *SimpleTime (int tim);
 char const *CalendarTime (int tim, int duration);
@@ -56,9 +57,12 @@ int DoSubst (ParsePtr p, DynamicBuffer *dbuf, Trigger *t, TimeTrig *tt, int dse,
 int DoSubstFromString (char const *source, DynamicBuffer *dbuf, int dse, int tim);
 int ParseLiteralDate (char const **s, int *dse, int *tim);
 int ParseLiteralTime (char const **s, int *tim);
+int evaluate_expr_node(expr_node *node, Value *locals, Value *ans, int *nonconst);
+void print_expr_tree(expr_node *node, FILE *fp);
+expr_node *free_expr_tree(expr_node *node);
 int EvalExpr (char const **e, Value *v, ParsePtr p);
 int DoCoerce (char type, Value *v);
-void PrintValue  (Value *v, FILE *fp);
+char const *PrintValue  (Value *v, FILE *fp);
 int CopyValue (Value *dest, const Value *src);
 int ReadLine (void);
 int OpenFile (char const *fname);
@@ -77,8 +81,9 @@ int JulianToGregorianOffset(int y, int m);
 int ParseChar (ParsePtr p, int *err, int peek);
 int ParseToken (ParsePtr p, DynamicBuffer *dbuf);
 int ParseIdentifier (ParsePtr p, DynamicBuffer *dbuf);
+expr_node * ParseExpr(ParsePtr p, int *r);
+void print_expr_nodes_stats(void);
 int EvaluateExpr (ParsePtr p, Value *v);
-int Evaluate (char const **s, Var *locals, ParsePtr p);
 int FnPopValStack (Value *val);
 void Eprint (char const *fmt, ...);
 void Wprint (char const *fmt, ...);
@@ -129,9 +134,10 @@ int StrCmpi (char const *s1, char const *s2);
 #endif

 Var *FindVar (char const *str, int create);
+SysVar *FindSysVar (char const *name);
 int DeleteVar (char const *str);
 int SetVar (char const *str, Value const *val);
-int GetVarValue (char const *str, Value *val, Var *locals, ParsePtr p);
+int GetVarValue (char const *str, Value *val);
 int DoSet  (Parser *p);
 int DoUnset  (Parser *p);
 int DoDump (ParsePtr p);
@@ -145,9 +151,10 @@ int ParseNonSpaceChar (ParsePtr p, int *err, int peek);
 unsigned int HashVal (char const *str);
 int DateOK (int y, int m, int d);
 Operator *FindOperator (char const *name, Operator where[], int num);
-BuiltinFunc *FindFunc (char const *name, BuiltinFunc where[], int num);
+BuiltinFunc *FindBuiltinFunc (char const *name);
 int InsertIntoSortBuffer (int dse, int tim, char const *body, int typ, int prio);
 void IssueSortedReminders (void);
+UserFunc *FindUserFunc(char const *name);
 int UserFuncExists (char const *fn);
 void DSEToHeb (int dse, int *hy, int *hm, int *hd);
 int HebNameToNum (char const *mname);
@@ -207,6 +214,7 @@ void set_cloexec(FILE *fp);
 int push_call(char const *filename, char const *func, int lineno);
 void clear_callstack(void);
 int print_callstack(FILE *fp);
+int have_callstack(void);
 void pop_call(void);
 void FixSpecialType(Trigger *trig);
 void WriteJSONTrigger(Trigger const *t, int include_tags, int today);
--- a/src/types.h
+++ b/src/types.h
@@ -30,21 +30,62 @@ typedef struct {
    int (*func)(void);
 } Operator;

+/* New-style expr_node structure and constants */
+enum expr_node_type
+{
+    N_FREE,
+    N_ERROR,
+    N_CONSTANT,
+    N_LOCAL_VAR,
+    N_SHORT_VAR,
+    N_VARIABLE,
+    N_SHORT_SYSVAR,
+    N_SYSVAR,
+    N_BUILTIN_FUNC,
+    N_SHORT_USER_FUNC,
+    N_USER_FUNC,
+    N_BINARY_OPERATOR,
+    N_UNARY_OPERATOR,
+};
+
 /* Structure for passing in Nargs and out RetVal from functions */
 typedef struct {
    int nargs;
+    Value *args;
    Value retval;
 } func_info;

+/* Forward reference */
+typedef struct expr_node_struct expr_node;
+
 /* Define the type of user-functions */
 typedef struct {
    char const *name;
    char minargs;
    char maxargs;
    char is_constant;
+    /* Old-style function calling convention */
    int (*func)(func_info *);
+
+    /* New-style function calling convention */
+    int (*newfunc)(expr_node *node, Value *locals, Value *ans, int *nonconst);
 } BuiltinFunc;

+#define SHORT_NAME_BUF 16
+typedef struct expr_node_struct {
+    struct expr_node_struct *child;
+    struct expr_node_struct *sibling;
+    enum expr_node_type type;
+    int num_kids;
+    union {
+        Value value;
+        int arg;
+        BuiltinFunc *builtin_func;
+        char name[SHORT_NAME_BUF];
+        int (*operator_func) (struct expr_node_struct *node, Value *locals, Value *ans, int *nonconst);
+    } u;
+} expr_node;
+
 /* Define the structure of a variable */
 typedef struct var {
    struct var *next;
@@ -142,6 +183,8 @@ typedef Parser *ParsePtr;  /* Pointer to parser structure */
 #define MSF_TYPE 7
 #define PASSTHRU_TYPE 8

+/* For function arguments */
+#define NO_MAX 127

 /* DEFINES for debugging flags */
 #define DB_PRTLINE      1
@@ -150,7 +193,7 @@ typedef Parser *ParsePtr;  /* Pointer to parser structure */
 #define DB_DUMP_VARS    8
 #define DB_ECHO_LINE   16
 #define DB_TRACE_FILES 32
-#define DB_EXPR_STACKS 64
+#define DB_PARSE_EXPR  64

 /* Enumeration of the tokens */
 enum TokTypes
@@ -244,3 +287,26 @@ typedef struct {
 #define TERMINAL_BACKGROUND_UNKNOWN -1
 #define TERMINAL_BACKGROUND_DARK    0
 #define TERMINAL_BACKGROUND_LIGHT   1
+
+typedef int (*SysVarFunc)(int, Value *);
+/* The structure of a system variable */
+typedef struct {
+    char const *name;
+    char modifiable;
+    int type;
+    void *value;
+    int min; /* Or const-value */
+    int max;
+} SysVar;
+
+/* Define the data structure used to hold a user-defined function */
+typedef struct udf_struct {
+    struct udf_struct *next;
+    char name[VAR_NAME_LEN+1];
+    expr_node *node;
+    char **args;
+    int nargs;
+    char const *filename;
+    int lineno;
+} UserFunc;
+
--- a/src/userfns.c
+++ b/src/userfns.c
@@ -30,34 +30,12 @@

 #define FUNC_HASH_SIZE 32   /* Size of User-defined function hash table */

-/* Define the data structure used to hold a user-defined function */
-typedef struct udf_struct {
-    struct udf_struct *next;
-    char name[VAR_NAME_LEN+1];
-    char const *text;
-    Var *locals;
-    char IsActive;
-    int nargs;
-    char const *filename;
-    int lineno;
-} UserFunc;
-
 /* The hash table */
 static UserFunc *FuncHash[FUNC_HASH_SIZE];

-/* Access to built-in functions */
-extern int NumFuncs;
-extern BuiltinFunc Func[];
-
-/* We need access to the expression evaluation stack */
-extern Value ValStack[];
-extern int ValStackPtr;
-
 static void DestroyUserFunc (UserFunc *f);
 static void FUnset (char const *name);
 static void FSet (UserFunc *f);
-static int SetUpLocalVars (UserFunc *f);
-static void DestroyLocalVals (UserFunc *f);

 /***************************************************************/
 /*                                                             */
@@ -98,9 +76,11 @@ int DoFset(ParsePtr p)
 {
    int r;
    int c;
+    int i;
    UserFunc *func;
-    Var *v;
-    Var *local;
+    UserFunc *existing;
+    Var *locals = NULL;
+    Var local_array[MAX_FUNC_ARGS];
    int orig_namelen;

    DynamicBuffer buf;
@@ -125,6 +105,18 @@ int DoFset(ParsePtr p)
 	return E_PARSE_ERR;
    }

+    /* If the function exists and was defined at the same line of the same
+       file, do nothing */
+    existing = FindUserFunc(DBufValue(&buf));
+    if (existing) {
+        if (!strcmp(existing->filename, FileName) &&
+            strcmp(existing->filename, "[cmdline]") &&
+            existing->lineno == LineNo) {
+            DBufFree(&buf);
+            /* We already have it!  Our work here is done. */
+            return OK;
+        }
+    }
    func = NEW(UserFunc);
    if (!func) {
 	DBufFree(&buf);
@@ -143,25 +135,22 @@ int DoFset(ParsePtr p)
    StrnCpy(func->name, DBufValue(&buf), VAR_NAME_LEN);
    DBufFree(&buf);
    if (!Hush) {
-	if (FindFunc(func->name, Func, NumFuncs)) {
+	if (FindBuiltinFunc(func->name)) {
 	    Eprint("%s: `%s'", ErrMsg[E_REDEF_FUNC], func->name);
 	}
    }
-    func->locals = NULL;
-    func->text = NULL;
-    func->IsActive = 0;
+    func->node = NULL;
    func->nargs = 0;
+    func->args = NULL;

-    /* Get the local variables - we insert the local variables in REVERSE
-       order, but that's OK, because we pop them off the stack in reverse
-       order, too, so everything works out just fine. */
+    /* Get the local variables */

    c=ParseNonSpaceChar(p, &r, 1);
    if (r) return r;
    if (c == ')') {
 	(void) ParseNonSpaceChar(p, &r, 0);
-    }
-    else {
+    } else {
+        locals = local_array;
 	while(1) {
 	    if ( (r=ParseIdentifier(p, &buf)) ) return r;
 	    if (*DBufValue(&buf) == '$') {
@@ -170,27 +159,24 @@ int DoFset(ParsePtr p)
 		return E_BAD_ID;
 	    }
            /* If we've already seen this local variable, error */
-            local = func->locals;
-            while(local) {
-                if (!StrinCmp(DBufValue(&buf), local->name, VAR_NAME_LEN)) {
+            for (i=0; i<func->nargs; i++) {
+                if (!StrinCmp(DBufValue(&buf), local_array[i].name, VAR_NAME_LEN)) {
                    DBufFree(&buf);
                    DestroyUserFunc(func);
                    return E_REPEATED_ARG;
                }
-                local = local->next;
            }
-	    v = NEW(Var);
-	    if (!v) {
-		DBufFree(&buf);
-		DestroyUserFunc(func);
-		return E_NO_MEM;
-	    }
+            i = func->nargs;
+            if (i >= MAX_FUNC_ARGS-1) {
+                DBufFree(&buf);
+                DestroyUserFunc(func);
+                return E_2MANY_ARGS;
+            }
+            local_array[i].v.type = ERR_TYPE;
+            StrnCpy(local_array[i].name, DBufValue(&buf), VAR_NAME_LEN);
+            local_array[i].next = &(local_array[i+1]);
+            local_array[i+1].next = NULL;
 	    func->nargs++;
-	    v->v.type = ERR_TYPE;
-	    StrnCpy(v->name, DBufValue(&buf), VAR_NAME_LEN);
-	    DBufFree(&buf);
-	    v->next = func->locals;
-	    func->locals = v;
 	    c = ParseNonSpaceChar(p, &r, 0);
 	    if (c == ')') break;
 	    else if (c != ',') {
@@ -205,7 +191,6 @@ int DoFset(ParsePtr p)
    if (c == '=') {
 	(void) ParseNonSpaceChar(p, &r, 0);
    }
-    /* Copy the text over */
    if (p->isnested) {
 	Eprint("%s", ErrMsg[E_CANTNEST_FDEF]);
 	DestroyUserFunc(func);
@@ -219,10 +204,23 @@ int DoFset(ParsePtr p)
        DestroyUserFunc(func);
        return E_EOLN;
    }
-    func->text = StrDup(p->pos);
-    if (!func->text) {
-	DestroyUserFunc(func);
-	return E_NO_MEM;
+    /* Parse the expression */
+    func->node = parse_expression(&(p->pos), &r, locals);
+    if (!func->node) {
+        DestroyUserFunc(func);
+        return r;
+    }
+
+    /* Save the argument names */
+    if (func->nargs) {
+        func->args = calloc(sizeof(char *), func->nargs);
+        for (i=0; i<func->nargs; i++) {
+            func->args[i] = StrDup(local_array[i].name);
+            if (!func->args[i]) {
+                DestroyUserFunc(func);
+                return E_NO_MEM;
+            }
+        }
    }

    /* If an old definition of this function exists, destroy it */
@@ -246,23 +244,22 @@ int DoFset(ParsePtr p)
 /***************************************************************/
 static void DestroyUserFunc(UserFunc *f)
 {
-    Var *v, *prev;
-
-    /* Free the local variables first */
-    v = f->locals;
-    while(v) {
-	DestroyValue(v->v);
-	prev = v;
-	v = v->next;
-	free(prev);
-    }
+    int i;

    /* Free the function definition */
-    if (f->text) free( (char *) f->text);
+    if (f->node) free_expr_tree(f->node);

    /* Free the filename */
    if (f->filename) free( (char *) f->filename);

+    /* Free arg names */
+    if (f->args) {
+        for (i=0; i<f->nargs; i++) {
+            if (f->args[i]) free(f->args[i]);
+        }
+        free(f->args);
+    }
+
    /* Free the data structure itself */
    free(f);
 }
@@ -308,129 +305,17 @@ static void FSet(UserFunc *f)
    FuncHash[h] = f;
 }

-/***************************************************************/
-/*                                                             */
-/*  CallUserFunc                                               */
-/*                                                             */
-/*  Call a user-defined function.                              */
-/*                                                             */
-/***************************************************************/
-int CallUserFunc(char const *name, int nargs, ParsePtr p)
+UserFunc *FindUserFunc(char const *name)
 {
-    UserFunc *f;
-    int h = HashVal(name) % FUNC_HASH_SIZE;
-    int i;
-    char const *s;
+   UserFunc *f;
+   int h = HashVal(name) % FUNC_HASH_SIZE;

-    /* Search for the function */
-    f = FuncHash[h];
-    while (f && StrinCmp(name, f->name, VAR_NAME_LEN)) f = f->next;
-    if (!f) {
-	Eprint("%s: `%s'", ErrMsg[E_UNDEF_FUNC], name);
-	return E_UNDEF_FUNC;
-    }
-    /* Debugging stuff */
-    if (DebugFlag & DB_PRTEXPR) {
-	fprintf(ErrFp, "%s %s(", ErrMsg[E_ENTER_FUN], f->name);
-	for (i=0; i<nargs; i++) {
-	    PrintValue(&ValStack[ValStackPtr - nargs + i], ErrFp);
-	    if (i<nargs-1) fprintf(ErrFp, ", ");
-	}
-	fprintf(ErrFp, ")\n");
-    }
-    /* Detect illegal recursive call */
-    if (f->IsActive) {
-	if (DebugFlag &DB_PRTEXPR) {
-	    fprintf(ErrFp, "%s %s() => ", ErrMsg[E_LEAVE_FUN], name);
-	    fprintf(ErrFp, "%s\n", ErrMsg[E_RECURSIVE]);
-	}
-	return E_RECURSIVE;
-    }
-
-    /* Check number of args */
-    if (nargs != f->nargs) {
-	if (DebugFlag &DB_PRTEXPR) {
-	    fprintf(ErrFp, "%s %s() => ", ErrMsg[E_LEAVE_FUN], name);
-	    fprintf(ErrFp, "%s\n",
-		    ErrMsg[(nargs < f->nargs) ? E_2FEW_ARGS : E_2MANY_ARGS]);
-	}
-	return (nargs < f->nargs) ? E_2FEW_ARGS : E_2MANY_ARGS;
-    }
-    /* Found the function - set up a local variable frame */
-    h = SetUpLocalVars(f);
-    if (h) {
-	if (DebugFlag &DB_PRTEXPR) {
-	    fprintf(ErrFp, "%s %s() => ", ErrMsg[E_LEAVE_FUN], name);
-	    fprintf(ErrFp, "%s\n", ErrMsg[h]);
-	}
-	return h;
-    }
-
-    /* Evaluate the expression */
-    f->IsActive = 1;
-    s = f->text;
-
-    /* Skip the opening bracket, if there's one */
-    while (isempty(*s)) s++;
-    if (*s == BEG_OF_EXPR) {
-        s++;
-    }
-    push_call(f->filename, f->name, f->lineno);
-    h = Evaluate(&s, f->locals, p);
-    if (h == OK) {
-        pop_call();
-    }
-    f->IsActive = 0;
-    DestroyLocalVals(f);
-    if (DebugFlag &DB_PRTEXPR) {
-	fprintf(ErrFp, "%s %s() => ", ErrMsg[E_LEAVE_FUN], name);
-	if (h) fprintf(ErrFp, "%s\n", ErrMsg[h]);
-	else {
-	    PrintValue(&ValStack[ValStackPtr-1], ErrFp);
-	    fprintf(ErrFp, "\n");
-	}
-    }
-    return h;
+   /* Search for the function */
+   f = FuncHash[h];
+   while (f && StrinCmp(name, f->name, VAR_NAME_LEN)) f = f->next;
+   return f;
 }

-/***************************************************************/
-/*                                                             */
-/*  SetUpLocalVars                                             */
-/*                                                             */
-/*  Set up the local variables from the stack frame.           */
-/*                                                             */
-/***************************************************************/
-static int SetUpLocalVars(UserFunc *f)
-{
-    int i, r;
-    Var *var;
-
-    for (i=0, var=f->locals; var && i<f->nargs; var=var->next, i++) {
-	if ( (r=FnPopValStack(&(var->v))) ) {
-	    DestroyLocalVals(f);
-	    return r;
-	}
-    }
-    return OK;
-}
-
-/***************************************************************/
-/*                                                             */
-/*  DestroyLocalVals                                           */
-/*                                                             */
-/*  Destroy the values of all local variables after evaluating */
-/*  the function.                                              */
-/*                                                             */
-/***************************************************************/
-static void DestroyLocalVals(UserFunc *f)
-{
-    Var *v = f->locals;
-
-    while(v) {
-	DestroyValue(v->v);
-	v = v->next;
-    }
-}
 /***************************************************************/
 /*                                                             */
 /*  UserFuncExists                                             */
@@ -441,12 +326,33 @@ static void DestroyLocalVals(UserFunc *f)
 /***************************************************************/
 int UserFuncExists(char const *fn)
 {
-    UserFunc *f;
-    int h = HashVal(fn) % FUNC_HASH_SIZE;
+    UserFunc *f = FindUserFunc(fn);

-    f = FuncHash[h];
-    while (f && StrinCmp(fn, f->name, VAR_NAME_LEN)) f = f->next;
    if (!f) return -1;
    else return f->nargs;
 }

+/***************************************************************/
+/*                                                             */
+/*  UnsetAllUserFuncs                                          */
+/*                                                             */
+/*  Call FUNSET on all user funcs.  Used with -ds flag to      */
+/*  ensure no expr_node memory leaks.                          */
+/*                                                             */
+/***************************************************************/
+void
+UnsetAllUserFuncs(void)
+{
+    UserFunc *f;
+    UserFunc *next;
+    int i;
+    for (i=0; i<FUNC_HASH_SIZE; i++) {
+        f = FuncHash[i];
+        while(f) {
+            next = f->next;
+            DestroyUserFunc(f);
+            f = next;
+        }
+        FuncHash[i] = NULL;
+    }
+}
--- a/src/utils.c
+++ b/src/utils.c
@@ -187,31 +187,33 @@ typedef struct cs_s {
 } cs;

 static cs *callstack = NULL;
+static cs *freecs = NULL;

 static void
 destroy_cs(cs *entry)
 {
-    if (entry->filename) free( (void *) entry->filename);
-    if (entry->func) free( (void *) entry->func);
-    free( (void *) entry);
+    entry->next = freecs;
+    freecs = entry;
 }


 int
 push_call(char const *filename, char const *func, int lineno)
 {
-    cs *entry = NEW(cs);
-    if (!entry) {
-        return E_NO_MEM;
+    cs *entry;
+    if (freecs) {
+        entry = freecs;
+        freecs = freecs->next;
+    } else {
+        entry = NEW(cs);
+        if (!entry) {
+            return E_NO_MEM;
+        }
    }
    entry->next = NULL;
-    entry->filename = StrDup(filename);
-    entry->func = StrDup(func);
+    entry->filename = filename;
+    entry->func = func;
    entry->lineno = lineno;
-    if (!entry->filename || !entry->func) {
-        destroy_cs(entry);
-        return E_NO_MEM;
-    }
    entry->next = callstack;
    callstack = entry;
    return OK;
@@ -233,11 +235,31 @@ clear_callstack(void)
 static void
 print_callstack_aux(FILE *fp, cs *entry)
 {
-    if (entry) {
-        print_callstack_aux(fp, entry->next);
-        fprintf(fp, "\n");
-        (void) fprintf(fp, "%s(%d): In function `%s'", entry->filename, entry->lineno, entry->func);
+    int i = 0;
+    char const *in = "In";
+    cs *prev = NULL;
+    while(entry) {
+        if (prev) {
+            fprintf(fp, "\n");
+            in = "Called from";
+        }
+        (void) fprintf(fp, "    %s(%d): [#%d] %s function `%s'", entry->filename, entry->lineno, i, in, entry->func);
+        prev = entry;
+        entry = entry->next;
+        i++;
+        if (i > 10) {
+            break;
+        }
    }
+    if (entry) {
+        (void) fprintf(fp, "\n    [remaining call frames omitted]");
+    }
+}
+
+int
+have_callstack(void)
+{
+    return (callstack != NULL);
 }

 int
--- a/src/var.c
+++ b/src/var.c
@@ -39,8 +39,6 @@ static int IntMax = INT_MAX;

 static Var *VHashTbl[VAR_HASH_SIZE];

-typedef int (*SysVarFunc)(int, Value *);
-
 static double
 strtod_in_c_locale(char const *str, char **endptr)
 {
@@ -511,20 +509,10 @@ int SetVar(char const *str, Value const *val)
 /*  Get a copy of the value of the variable.                   */
 /*                                                             */
 /***************************************************************/
-int GetVarValue(char const *str, Value *val, Var *locals, ParsePtr p)
+int GetVarValue(char const *str, Value *val)
 {
    Var *v;

-    /* Try searching local variables first */
-    v = locals;
-    while (v) {
-	if (! StrinCmp(str, v->name, VAR_NAME_LEN))
-	    return CopyValue(val, &v->v);
-	v = v->next;
-    }
-
-    /* Global variable... mark expression as non-constant */
-    if (p) p->nonconst_expr = 1;
    v=FindVar(str, 0);

    if (!v) {
@@ -785,16 +773,6 @@ int DoPreserve (Parser *p)
 /*                                                             */
 /***************************************************************/

-/* The structure of a system variable */
-typedef struct {
-    char const *name;
-    char modifiable;
-    int type;
-    void *value;
-    int min; /* Or const-value */
-    int max;
-} SysVar;
-
 /* Macro to access "min" but as a constval.  Just to make source more
   readable */
 #define constval min
@@ -919,7 +897,6 @@ static SysVar SysVarArr[] = {
 };

 #define NUMSYSVARS ( sizeof(SysVarArr) / sizeof(SysVar) )
-static SysVar *FindSysVar (char const *name);
 static void DumpSysVar (char const *name, const SysVar *v);
 /***************************************************************/
 /*                                                             */
@@ -1016,7 +993,7 @@ int GetSysVar(char const *name, Value *val)
 /* Find a system var with specified name.                      */
 /*                                                             */
 /***************************************************************/
-static SysVar *FindSysVar(char const *name)
+SysVar *FindSysVar(char const *name)
 {
    int top=NUMSYSVARS-1, bottom=0;
    int mid=(top + bottom) / 2;
--- a/tests/ansicolors.rem
+++ b/tests/ansicolors.rem
@@ -35,8 +35,8 @@ set a ansicolor(-1, 0, 0)
 set a ansicolor(42, 42, 256)
 set a ansicolor("foo")
 set a ansicolor("1 1")
-set a ansicolor("-1 -1 0");
-set a ansicolor("256 1 1");
+set a ansicolor("-1 -1 0")
+set a ansicolor("256 1 1")
 set a ansicolor(128, 128, 128, 2)
 set a ansicolor(128, 128, 128, -1)
 set a ansicolor(128, 128, 128, 0, 2)