Added. moved from filter-sexp.[ch]

2000-02-28  NotZed  <NotZed@HelixCode.com>

        * e-util/e-sexp.[ch]: Added.  moved from filter-sexp.[ch]

        * e-util/Makefile.am (libeutil_a_SOURCES): Add e-sexp.
        (noinst_LTLIBRARIES): Changed to a libtool library.

        * Makefile.am (SUBDIRS): Build e-util before other stuff.
        (SUBDIRS): Build filter after camel.

svn path=/trunk/; revision=1980

3 files changed, 1208 insertions, 3 deletions

diff --git a/e-util/Makefile.am b/e-util/Makefile.am
index c6058791dd..2b1098a5d2 100644
--- a/e-util/Makefile.am
+++ b/e-util/Makefile.am
@@ -1,9 +1,9 @@
 INCLUDES =					\
 	$(GNOME_INCLUDEDIR)
 
-noinst_LIBRARIES = libeutil.a
+noinst_LTLIBRARIES = libeutil.la
 
-libeutil_a_SOURCES = \
+libeutil_la_SOURCES = \
 	e-canvas.c	\
 	e-canvas.h	\
 	e-canvas-utils.c\
@@ -17,4 +17,6 @@ libeutil_a_SOURCES = \
 	e-util.c	\
 	e-util.h	\
 	e-xml-utils.c	\
-	e-xml-utils.h
+	e-xml-utils.h	\
+	e-sexp.c	\
+	s-sexp.h
diff --git a/e-util/e-sexp.c b/e-util/e-sexp.c
new file mode 100644
index 0000000000..b1438c1468
--- /dev/null
+++ b/e-util/e-sexp.c
@@ -0,0 +1,1088 @@
+/* 
+ * Copyright 2000 HelixCode (http://www.helixcode.com).
+ *
+ * A simple, extensible s-exp evaluation engine.
+ *
+ * Author : 
+ *  Michael Zucchi <notzed@helixcode.com>
+
+ * This program is free software; you can redistribute it and/or 
+ * modify it under the terms of the GNU General Public License as 
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
+ */
+
+/*
+  The following built-in s-exp's are supported:
+
+  list = (and list*)
+	perform an intersection of a number of lists, and return that.
+
+  bool = (and bool*)
+	perform a boolean AND of boolean values.
+
+  list = (or list*)
+	perform a union of a number of lists, returning the new list.
+
+  bool = (or bool*)
+	perform a boolean OR of boolean values.
+
+  int = (+ int*)
+	Add integers.
+
+  string = (+ string*)
+	Concat strings.
+
+  int = (- int int*)
+	Subtract integers from the first.
+
+  Comparison operators:
+
+  bool = (< int int)
+  bool = (> int int)
+  bool = (= int int)
+
+  bool = (< string string)
+  bool = (> string string)
+  bool = (= string string)
+	Perform a comparision of 2 integers, or 2 string values.
+
+  Function flow:
+
+  type = (if bool function)
+  type = (if bool function function)
+  	Choose a flow path based on a boolean value
+
+  type = (begin  func func func)
+        Execute a sequence.  The last function return is the return type.
+*/
+
+#include <glib.h>
+#include <stdio.h>
+#include <time.h>
+#include <string.h>
+
+#include "e-sexp.h"
+
+#define p(x)			/* parse debug */
+#define r(x)			/* run debug */
+#define d(x)			/* general debug */
+
+
+static struct _ESExpTerm * parse_list(ESExp *f, int gotbrace);
+static struct _ESExpTerm * parse_value(ESExp *f);
+
+static void parse_dump_term(struct _ESExpTerm *t, int depth);
+
+static GtkObjectClass *parent_class;
+
+
+
+static GScannerConfig scanner_config =
+{
+	( " \t\r\n")		/* cset_skip_characters */,
+	( G_CSET_a_2_z
+	  "_+<=>"
+	  G_CSET_A_2_Z)		/* cset_identifier_first */,
+	( G_CSET_a_2_z
+	  "_0123456789-<>"
+	  G_CSET_A_2_Z
+	  G_CSET_LATINS
+	  G_CSET_LATINC	)	/* cset_identifier_nth */,
+	( ";\n" )		/* cpair_comment_single */,
+  
+	FALSE			/* case_sensitive */,
+  
+	TRUE			/* skip_comment_multi */,
+	TRUE			/* skip_comment_single */,
+	TRUE			/* scan_comment_multi */,
+	TRUE			/* scan_identifier */,
+	TRUE			/* scan_identifier_1char */,
+	FALSE			/* scan_identifier_NULL */,
+	TRUE			/* scan_symbols */,
+	FALSE			/* scan_binary */,
+	TRUE			/* scan_octal */,
+	TRUE			/* scan_float */,
+	TRUE			/* scan_hex */,
+	FALSE			/* scan_hex_dollar */,
+	TRUE			/* scan_string_sq */,
+	TRUE			/* scan_string_dq */,
+	TRUE			/* numbers_2_int */,
+	FALSE			/* int_2_float */,
+	FALSE			/* identifier_2_string */,
+	TRUE			/* char_2_token */,
+	FALSE			/* symbol_2_token */,
+	FALSE			/* scope_0_fallback */,
+};
+
+struct _ESExpResult *
+e_sexp_result_new(int type)
+{
+	struct _ESExpResult *r = g_malloc0(sizeof(*r));
+	r->type = type;
+	return r;
+}
+
+void
+e_sexp_result_free(struct _ESExpResult *t)
+{
+	if (t == NULL)
+		return;
+
+	switch(t->type) {
+	case ESEXP_RES_ARRAY_PTR:
+		g_ptr_array_free(t->value.ptrarray, TRUE);
+		break;
+	case ESEXP_RES_BOOL:
+	case ESEXP_RES_INT:
+		break;
+	case ESEXP_RES_STRING:
+		g_free(t->value.string);
+		break;
+	case ESEXP_RES_UNDEFINED:
+		break;
+	}
+	g_free(t);
+}
+
+/* implementations for the builtin functions */
+
+/* can you tell, i dont like glib? */
+/* we can only itereate a hashtable from a called function */
+struct _glib_sux_donkeys {
+	int count;
+	GPtrArray *uids;
+};
+
+/* ok, store any values that are in all sets */
+static void
+g_lib_sux_htand(char *key, int value, struct _glib_sux_donkeys *fuckup)
+{
+	if (value == fuckup->count) {
+		g_ptr_array_add(fuckup->uids, key);
+	}
+}
+
+/* or, store all unique values */
+static void
+g_lib_sux_htor(char *key, int value, struct _glib_sux_donkeys *fuckup)
+{
+	g_ptr_array_add(fuckup->uids, key);
+}
+
+static ESExpResult *
+term_eval_and(struct _ESExp *f, int argc, struct _ESExpTerm **argv, void *data)
+{
+	struct _ESExpResult *r, *r1;
+	GHashTable *ht = g_hash_table_new(g_str_hash, g_str_equal);
+	struct _glib_sux_donkeys lambdafoo;
+	int type=-1;
+	int bool = TRUE;
+	int i;
+	
+	r(printf("( and\n"));
+
+	r = e_sexp_result_new(ESEXP_RES_UNDEFINED);
+	
+	for (i=0;bool && i<argc;i++) {
+		r1 = e_sexp_term_eval(f, argv[i]);
+		if (type == -1)
+			type = r1->type;
+		if (type != r1->type) {
+			printf("invalid types in and operation, all types must be the same\n");
+		} else if ( r1->type == ESEXP_RES_ARRAY_PTR ) {
+			char **a1;
+			int l1, j;
+			
+			a1 = (char **)r1->value.ptrarray->pdata;
+			l1 = r1->value.ptrarray->len;
+			for (j=0;j<l1;j++) {
+				int n;
+				n = (int)g_hash_table_lookup(ht, a1[j]);
+				g_hash_table_insert(ht, a1[j], (void *)n+1);
+			}
+		} else if ( r1->type == ESEXP_RES_BOOL ) {
+			bool &= r1->value.bool;
+		}
+		e_sexp_result_free(r1);
+	}
+	
+	if (type == ESEXP_RES_ARRAY_PTR) {
+		lambdafoo.count = argc;
+		lambdafoo.uids = g_ptr_array_new();
+		g_hash_table_foreach(ht, (GHFunc)g_lib_sux_htand, &lambdafoo);
+		r->type = ESEXP_RES_ARRAY_PTR;
+		r->value.ptrarray = lambdafoo.uids;
+	} else if (type == ESEXP_RES_BOOL) {
+		r->type = ESEXP_RES_BOOL;
+		r->value.bool = bool;
+	}
+	
+	g_hash_table_destroy(ht);
+	
+	return r;
+}
+
+static ESExpResult *
+term_eval_or(struct _ESExp *f, int argc, struct _ESExpTerm **argv, void *data)
+{
+	struct _ESExpResult *r, *r1;
+	GHashTable *ht = g_hash_table_new(g_str_hash, g_str_equal);
+	struct _glib_sux_donkeys lambdafoo;
+	int type = -1;
+	int bool = FALSE;
+	int i;
+	
+	r(printf("(or \n"));
+
+	r = e_sexp_result_new(ESEXP_RES_UNDEFINED);
+	
+	for (i=0;!bool && i<argc;i++) {
+		r1 = e_sexp_term_eval(f, argv[i]);
+		if (type == -1)
+			type = r1->type;
+		if (r1->type != type) {
+			printf("wrong types in or operation\n");
+		} else if (r1->type == ESEXP_RES_ARRAY_PTR) {
+			char **a1;
+			int l1, j;
+			
+			a1 = (char **)r1->value.ptrarray->pdata;
+			l1 = r1->value.ptrarray->len;
+			for (j=0;j<l1;j++) {
+				g_hash_table_insert(ht, a1[j], (void *)1);
+			}
+		} else if (r1->type == ESEXP_RES_BOOL) {
+			bool |= r1->value.bool;				
+		}
+		e_sexp_result_free(r1);
+	}
+	
+	if (type == ESEXP_RES_ARRAY_PTR) {
+		lambdafoo.count = argc;
+		lambdafoo.uids = g_ptr_array_new();
+		g_hash_table_foreach(ht, (GHFunc)g_lib_sux_htor, &lambdafoo);
+		r->type = ESEXP_RES_ARRAY_PTR;
+		r->value.ptrarray = lambdafoo.uids;
+	} else if (type == ESEXP_RES_BOOL) {
+		r->type = ESEXP_RES_BOOL;
+		r->value.bool = bool;
+	}
+	g_hash_table_destroy(ht);
+	
+	return r;
+}
+
+static ESExpResult *
+term_eval_not(struct _ESExp *f, int argc, struct _ESExpResult **argv, void *data)
+{
+	int res = TRUE;
+	ESExpResult *r;
+
+	if (argc>0) {
+		if (argv[0]->type == ESEXP_RES_BOOL
+		    && argv[0]->value.bool)
+			res = FALSE;
+	}
+	r = e_sexp_result_new(ESEXP_RES_BOOL);
+	r->value.bool = res;
+	return r;
+}
+
+/* this should support all arguments ...? */
+static ESExpResult *
+term_eval_lt(struct _ESExp *f, int argc, struct _ESExpTerm **argv, void *data)
+{
+	struct _ESExpResult *r, *r1, *r2;
+
+	r = e_sexp_result_new(ESEXP_RES_UNDEFINED);
+	
+	if (argc == 2) {
+		r1 = e_sexp_term_eval(f, argv[0]);
+		r2 = e_sexp_term_eval(f, argv[1]);
+		if (r1->type != r2->type) {
+			printf("error, invalid types in compare\n");
+		} else if (r1->type == ESEXP_RES_INT) {
+			r->type = ESEXP_RES_BOOL;
+			r->value.bool = r1->value.number < r2->value.number;
+		} else if (r1->type == ESEXP_RES_STRING) {
+			r->type = ESEXP_RES_BOOL;
+			r->value.bool = strcmp(r1->value.string, r2->value.string) < 0;
+		}
+	}
+	return r;
+}
+
+/* this should support all arguments ...? */
+static ESExpResult *
+term_eval_gt(struct _ESExp *f, int argc, struct _ESExpTerm **argv, void *data)
+{
+	struct _ESExpResult *r, *r1, *r2;
+
+	r = e_sexp_result_new(ESEXP_RES_UNDEFINED);
+	
+	if (argc == 2) {
+		r1 = e_sexp_term_eval(f, argv[0]);
+		r2 = e_sexp_term_eval(f, argv[1]);
+		if (r1->type != r2->type) {
+			printf("error, invalid types in compare\n");
+		} else if (r1->type == ESEXP_RES_INT) {
+			r->type = ESEXP_RES_BOOL;
+			r->value.bool = r1->value.number > r2->value.number;
+		} else if (r1->type == ESEXP_RES_STRING) {
+			r->type = ESEXP_RES_BOOL;
+			r->value.bool = strcmp(r1->value.string, r2->value.string) > 0;
+		}
+	}
+	return r;
+}
+
+/* this should support all arguments ...? */
+static ESExpResult *
+term_eval_eq(struct _ESExp *f, int argc, struct _ESExpTerm **argv, void *data)
+{
+	struct _ESExpResult *r, *r1, *r2;
+
+	r = e_sexp_result_new(ESEXP_RES_BOOL);
+	
+	if (argc == 2) {
+		r1 = e_sexp_term_eval(f, argv[0]);
+		r2 = e_sexp_term_eval(f, argv[1]);
+		if (r1->type != r2->type) {
+			r->value.bool = FALSE;
+		} else if (r1->type == ESEXP_RES_INT) {
+			r->value.bool = r1->value.number == r2->value.number;
+		} else if (r1->type == ESEXP_RES_BOOL) {
+			r->value.bool = r1->value.bool == r2->value.bool;
+		} else if (r1->type == ESEXP_RES_STRING) {
+			r->value.bool = strcmp(r1->value.string, r2->value.string) == 0;
+		}
+	}
+	return r;
+}
+
+static ESExpResult *
+term_eval_plus(struct _ESExp *f, int argc, struct _ESExpResult **argv, void *data)
+{
+	struct _ESExpResult *r=NULL;
+	int type;
+	int i;
+
+	if (argc>0) {
+		type = argv[0]->type;
+		switch(type) {
+		case ESEXP_RES_INT: {
+			int total = argv[0]->value.number;
+			for (i=1;i<argc && argv[i]->type == ESEXP_RES_INT;i++) {
+				total += argv[i]->value.number;
+			}
+			if (i<argc) {
+				g_warning("Wrong type trying to add integers: ignored");
+			}
+			r = e_sexp_result_new(ESEXP_RES_INT);
+			r->value.number = total;
+			break; }
+		case ESEXP_RES_STRING: {
+			GString *s = g_string_new(argv[0]->value.string);
+			for (i=1;i<argc && argv[i]->type == ESEXP_RES_STRING;i++) {
+				g_string_append(s, argv[i]->value.string);
+			}
+			if (i<argc) {
+				g_warning("Wrong type trying to concat strings: ignored");
+			}
+			r = e_sexp_result_new(ESEXP_RES_STRING);
+			r->value.string = s->str;
+			g_string_free(s, FALSE);
+			break; }
+			
+		}
+	}
+
+	if (!r) {
+		r = e_sexp_result_new(ESEXP_RES_INT);
+		r->value.number = 0;
+	}
+	return r;
+}
+
+static ESExpResult *
+term_eval_sub(struct _ESExp *f, int argc, struct _ESExpResult **argv, void *data)
+{
+	struct _ESExpResult *r=NULL;
+	int type;
+	int i;
+
+	if (argc>0) {
+		type = argv[0]->type;
+		switch(type) {
+		case ESEXP_RES_INT: {
+			int total = argv[0]->value.number;
+			for (i=1;i<argc && argv[i]->type == ESEXP_RES_INT;i++) {
+				total -= argv[i]->value.number;
+			}
+			if (i<argc) {
+				g_warning("Wrong type trying to subtract numbers: ignored");
+			}
+			r = e_sexp_result_new(ESEXP_RES_INT);
+			r->value.number = total;
+			break; }
+		}
+	}
+
+	if (!r) {
+		r = e_sexp_result_new(ESEXP_RES_INT);
+		r->value.number = 0;
+	}
+	return r;
+}
+
+/* implements 'if' function */
+static ESExpResult *
+term_eval_if(struct _ESExp *f, int argc, struct _ESExpTerm **argv, void *data)
+{
+	struct _ESExpResult *r;
+	int doit;
+
+	if (argc >=2 && argc<=3) {
+		r = e_sexp_term_eval(f, argv[0]);
+		doit = (r->type == ESEXP_RES_BOOL && r->value.bool);
+		e_sexp_result_free(r);
+		if (doit) {
+			return e_sexp_term_eval(f, argv[1]);
+		} else if (argc>2) {
+			return e_sexp_term_eval(f, argv[2]);
+		}
+	}
+	return e_sexp_result_new(ESEXP_RES_UNDEFINED);
+}
+
+/* implements 'begin' statement */
+static ESExpResult *
+term_eval_begin(struct _ESExp *f, int argc, struct _ESExpTerm **argv, void *data)
+{
+	struct _ESExpResult *r=NULL;
+	int i;
+
+	for (i=0;i<argc;i++) {
+		if (r)
+			e_sexp_result_free(r);
+		r = e_sexp_term_eval(f, argv[i]);
+	}
+	if (r)
+		return r;
+	else
+		return e_sexp_result_new(ESEXP_RES_UNDEFINED);
+}
+
+
+struct _ESExpResult *
+e_sexp_term_eval(struct _ESExp *f, struct _ESExpTerm *t)
+{
+	struct _ESExpResult *r, *r1;
+	int i;
+
+	r(printf("eval term :\n"));
+	r(parse_dump_term(t, 0));
+
+	r = g_malloc0(sizeof(*r));
+	r->type = ESEXP_RES_UNDEFINED;
+
+	switch (t->type) {
+	case ESEXP_TERM_STRING:
+		r(printf(" (string \"%s\")\n", t->value.string));
+		r->type = ESEXP_RES_STRING;
+		/* erk, this shoul;dn't need to strdup this ... */
+		r->value.string = g_strdup(t->value.string);
+		break;
+	case ESEXP_TERM_INT:
+		r(printf(" (int %d)\n", t->value.number));
+		r->type = ESEXP_RES_INT;
+		r->value.number = t->value.number;
+		break;
+	case ESEXP_TERM_BOOL:
+		r(printf(" (int %d)\n", t->value.number));
+		r->type = ESEXP_RES_BOOL;
+		r->value.bool = t->value.bool;
+		break;
+	case ESEXP_TERM_IFUNC: {
+		if (t->value.func.sym->f.ifunc) {
+			r1 = t->value.func.sym->f.ifunc(f, t->value.func.termcount, t->value.func.terms, t->value.func.sym->data);
+			if (r1) {
+				e_sexp_result_free(r);
+				r = r1;
+			}
+		}
+		break; }
+	case ESEXP_TERM_FUNC: {
+		struct _ESExpResult **argv;
+
+		/* first evaluate all arguments to result types */
+		argv = alloca(sizeof(argv[0]) * t->value.func.termcount);
+		for (i=0;i<t->value.func.termcount;i++) {
+			argv[i] = e_sexp_term_eval(f, t->value.func.terms[i]);
+		}
+		/* call the function */
+		if (t->value.func.sym->f.func) {
+			r1 = t->value.func.sym->f.func(f, t->value.func.termcount, argv, t->value.func.sym->data);
+			if (r1) {
+				e_sexp_result_free(r);
+				r = r1;
+			}
+		}
+		for (i=0;i<t->value.func.termcount;i++) {
+			e_sexp_result_free(argv[i]);
+		}
+		break; }
+	default:
+		printf("Warning: Unknown type encountered in parse tree: %d\n", t->type);
+		r->type = ESEXP_RES_UNDEFINED;
+	}
+
+	return r;
+}
+
+
+static void
+eval_dump_result(ESExpResult *r, int depth)
+{
+	int i;
+	
+	if (r==NULL) {
+		printf("null result???\n");
+		return;
+	}
+
+	for (i=0;i<depth;i++)
+		printf("   ");
+
+	switch (r->type) {
+	case ESEXP_RES_ARRAY_PTR:
+		printf("array pointers\n");
+		break;
+	case ESEXP_RES_INT:
+		printf("int: %d\n", r->value.number);
+		break;
+	case ESEXP_RES_STRING:
+		printf("string: '%s'\n", r->value.string);
+		break;
+	case ESEXP_RES_BOOL:
+		printf("bool: %c\n", r->value.bool?'t':'f');
+		break;
+	case ESEXP_RES_UNDEFINED:
+		printf(" <undefined>\n");
+		break;
+	}
+	printf("\n");
+}
+
+static void
+parse_dump_term(struct _ESExpTerm *t, int depth)
+{
+	int i;
+
+	if (t==NULL) {
+		printf("null term??\n");
+		return;
+	}
+
+	for (i=0;i<depth;i++)
+		printf("   ");
+	
+	switch (t->type) {
+	case ESEXP_TERM_STRING:
+		printf(" \"%s\"", t->value.string);
+		break;
+	case ESEXP_TERM_INT:
+		printf(" %d", t->value.number);
+		break;
+	case ESEXP_TERM_BOOL:
+		printf(" #%c", t->value.bool?'t':'f');
+		break;
+	case ESEXP_TERM_IFUNC:
+	case ESEXP_TERM_FUNC:
+		printf(" (function %s\n", t->value.func.sym->name);
+		/*printf(" [%d] ", t->value.func.termcount);*/
+		for (i=0;i<t->value.func.termcount;i++) {
+			parse_dump_term(t->value.func.terms[i], depth+1);
+		}
+		for (i=0;i<depth;i++)
+			printf("   ");
+		printf(" )");
+		break;
+	case ESEXP_TERM_VAR:
+		printf(" (variable %s )\n", t->value.var->name);
+		break;
+	default:
+		printf("unknown type: %d\n", t->type);
+	}
+
+	printf("\n");
+}
+
+/*
+  PARSER
+*/
+
+static struct _ESExpTerm *
+parse_new_term(int type)
+{
+	struct _ESExpTerm *s = g_malloc0(sizeof(*s));
+	s->type = type;
+	return s;
+}
+
+static void
+parse_term_free(struct _ESExpTerm *t)
+{
+	int i;
+
+	if (t==NULL) {
+		return;
+	}
+	
+	switch (t->type) {
+	case ESEXP_TERM_FUNC:
+	case ESEXP_TERM_IFUNC:
+		for (i=0;i<t->value.func.termcount;i++) {
+			parse_term_free(t->value.func.terms[i]);
+		}
+		g_free(t->value.func.terms);
+		break;
+	case ESEXP_TERM_VAR:
+		break;
+	case ESEXP_TERM_STRING:
+		g_free(t->value.string);
+		break;
+	case ESEXP_TERM_INT:
+		break;
+	default:
+		printf("parse_term_free: unknown type: %d\n", t->type);
+	}
+	g_free(t);
+}
+
+static struct _ESExpTerm **
+parse_values(ESExp *f, int *len)
+{
+	int token;
+	struct _ESExpTerm **terms;
+	int i=0;
+	GScanner *gs = f->scanner;
+
+	p(printf("parsing values\n"));
+
+	/* FIXME: This hardcoded nonsense!!! :) */
+	terms = g_malloc0(20*sizeof(*terms));
+
+	while ( (token = g_scanner_peek_next_token(gs)) != G_TOKEN_EOF
+		&& token != ')') {
+		terms[i]=parse_value(f);
+		i++;
+	}
+
+	p(printf("found %d subterms\n", i));
+	*len = i;
+	
+	p(printf("dont parsing values\n"));
+	return terms;
+}
+
+static struct _ESExpTerm *
+parse_value(ESExp *f)
+{
+	int token;
+	struct _ESExpTerm *t = NULL;
+	GScanner *gs = f->scanner;
+	struct _ESExpSymbol *s;
+
+	p(printf("parsing value\n"));
+
+	token = g_scanner_get_next_token(gs);
+	switch(token) {
+	case G_TOKEN_LEFT_PAREN:
+		p(printf("got brace, its a list!\n"));
+		return parse_list(f, TRUE);
+	case G_TOKEN_STRING:
+		p(printf("got string\n"));
+		t = parse_new_term(ESEXP_TERM_STRING);
+		t->value.string = g_strdup(g_scanner_cur_value(gs).v_string);
+		break;
+	case G_TOKEN_INT:
+		t = parse_new_term(ESEXP_TERM_INT);
+		t->value.number = g_scanner_cur_value(gs).v_int;
+		p(printf("got int\n"));
+		break;
+	case '#':
+		printf("got bool?\n");
+		token = g_scanner_get_next_token(gs);
+		t = parse_new_term(ESEXP_TERM_BOOL);
+		t->value.bool = token=='t';
+		break;
+	case G_TOKEN_SYMBOL:
+		s = g_scanner_cur_value(gs).v_symbol;
+		switch (s->type) {
+		case ESEXP_TERM_FUNC:
+		case ESEXP_TERM_IFUNC:
+				/* this is basically invalid, since we can't use function
+				   pointers, but let the runtime catch it ... */
+			t = parse_new_term(s->type);
+			t->value.func.sym = s;
+			t->value.func.terms = parse_values(f, &t->value.func.termcount);
+			break;
+		case ESEXP_TERM_VAR:
+			t = parse_new_term(s->type);
+			t->value.var = s;
+			break;
+		default:
+			printf("Invalid symbol type: %d\n", s->type);
+		}
+		break;
+	case G_TOKEN_IDENTIFIER:
+		printf("Unknown identifier encountered: %s\n", g_scanner_cur_value(gs).v_identifier);
+		break;
+	default:
+		printf("Innvalid token trying to parse a list of values\n");
+	}
+	p(printf("done parsing value\n"));
+	return t;
+}
+
+/* FIXME: this needs some robustification */
+static struct _ESExpTerm *
+parse_list(ESExp *f, int gotbrace)
+{
+	int token;
+	struct _ESExpTerm *t = NULL;
+	GScanner *gs = f->scanner;
+
+	p(printf("parsing list\n"));
+	if (gotbrace)
+		token = '(';
+	else
+		token = g_scanner_get_next_token(gs);
+	if (token =='(') {
+		token = g_scanner_get_next_token(gs);
+		switch(token) {
+		case G_TOKEN_SYMBOL: {
+			struct _ESExpSymbol *s;
+
+			s = g_scanner_cur_value(gs).v_symbol;
+			p(printf("got funciton: %s\n", s->name));
+			t = parse_new_term(s->type);
+			p(printf("created new list %p\n", t));
+			/* if we have a variable, find out its base type */
+			while (s->type == ESEXP_TERM_VAR) {
+				s = ((ESExpTerm *)(s->data))->value.var;
+			}
+			if (s->type == ESEXP_TERM_FUNC
+			    || s->type == ESEXP_TERM_IFUNC) {
+				t->value.func.sym = s;
+				t->value.func.terms = parse_values(f, &t->value.func.termcount);
+			} else {
+				printf("Error, trying to call variable as function\n");
+			}
+			break; }
+		case G_TOKEN_IDENTIFIER:
+			printf("Unknown identifier: %s\n", g_scanner_cur_value(gs).v_identifier);
+			break;
+		default:
+			printf("unknown sequence encountered, type = %d\n", token);
+		}
+		token = g_scanner_get_next_token(gs);
+		if (token != ')') {
+			printf("Error, expected ')' not found\n");
+		}
+	} else {
+		printf("Error, list term without opening (\n");
+	}
+
+	p(printf("returning list %p\n", t));
+	return t;
+}
+
+#if 0
+GList *
+camel_mbox_folder_search_by_expression(CamelFolder *folder, char *expression, CamelException *ex)
+{
+	GScanner *gs;
+	int i;
+	struct _ESExpTerm *t;
+	struct _searchcontext *ctx;
+	struct _ESExpResult *r;
+	GList *matches = NULL;
+
+	gs = g_scanner_new(&scanner_config);
+	for(i=0;i<sizeof(symbols)/sizeof(symbols[0]);i++)
+		g_scanner_scope_add_symbol(gs, 0, symbols[i].name, &symbols[i]);
+
+	g_scanner_input_text(gs, expression, strlen(expression));
+	t = parse_list(gs, 0);
+
+	if (t) {
+		ctx = g_malloc0(sizeof(*ctx));
+		ctx->folder = folder;
+		ctx->summary = camel_folder_get_summary(folder, ex);
+		ctx->message_info = camel_folder_summary_get_message_info_list(ctx->summary);
+#ifdef HAVE_IBEX
+		ctx->index = ibex_open(CAMEL_MBOX_FOLDER(folder)->index_file_path, FALSE);
+		if (!ctx->index) {
+			perror("Cannot open index file, body searches will be ignored\n");
+		}
+#endif
+		r = term_eval(ctx, t);
+
+		/* now create a folder summary to return?? */
+		if (r
+		    && r->type == ESEXP_RES_ARRAY_PTR) {
+			d(printf("got result ...\n"));
+			for (i=0;i<r->value.ptrarray->len;i++) {
+				d(printf("adding match: %s\n", (char *)g_ptr_array_index(r->value.ptrarray, i)));
+				matches = g_list_prepend(matches, g_strdup(g_ptr_array_index(r->value.ptrarray, i)));
+			}
+			e_sexp_result_free(r);
+		}
+
+		if (ctx->index)
+			ibex_close(ctx->index);
+
+		gtk_object_unref((GtkObject *)ctx->summary);
+		g_free(ctx);
+		parse_term_free(t);
+	} else {
+		printf("Warning, Could not parse expression!\n %s\n", expression);
+	}
+
+	g_scanner_destroy(gs);
+
+	return matches;
+}
+#endif
+
+
+static void
+e_sexp_class_init (ESExpClass *class)
+{
+	GtkObjectClass *object_class;
+	
+	object_class = (GtkObjectClass *) class;
+	parent_class = gtk_type_class (gtk_object_get_type ());
+}
+
+/* 'builtin' functions */
+static struct {
+	char *name;
+	ESExpFunc *func;
+	int type;		/* set to 1 if a function can perform shortcut evaluation, or
+				   doesn't execute everything, 0 otherwise */
+} symbols[] = {
+	{ "and", (ESExpFunc *)term_eval_and, 1 },
+	{ "or", (ESExpFunc *)term_eval_or, 1 },
+	{ "not", (ESExpFunc *)term_eval_not, 0 },
+	{ "<", (ESExpFunc *)term_eval_lt, 1 },
+	{ ">", (ESExpFunc *)term_eval_gt, 1 },
+	{ "=", (ESExpFunc *)term_eval_eq, 1 },
+	{ "+", (ESExpFunc *)term_eval_plus, 0 },
+	{ "-", (ESExpFunc *)term_eval_sub, 0 },
+	{ "if", (ESExpFunc *)term_eval_if, 1 },
+	{ "begin", (ESExpFunc *)term_eval_begin, 1 },
+};
+
+static void
+e_sexp_init (ESExp *s)
+{
+	int i;
+
+	s->scanner = g_scanner_new(&scanner_config);
+
+	/* load in builtin symbols? */
+	for(i=0;i<sizeof(symbols)/sizeof(symbols[0]);i++) {
+		if (symbols[i].type == 1) {
+			e_sexp_add_ifunction(s, 0, symbols[i].name, (ESExpIFunc *)symbols[i].func, &symbols[i]);
+		} else {
+			e_sexp_add_function(s, 0, symbols[i].name, symbols[i].func, &symbols[i]);
+		}
+	}
+}
+
+guint
+e_sexp_get_type (void)
+{
+	static guint type = 0;
+	
+	if (!type) {
+		GtkTypeInfo type_info = {
+			"ESExp",
+			sizeof (ESExp),
+			sizeof (ESExpClass),
+			(GtkClassInitFunc) e_sexp_class_init,
+			(GtkObjectInitFunc) e_sexp_init,
+			(GtkArgSetFunc) NULL,
+			(GtkArgGetFunc) NULL
+		};
+		
+		type = gtk_type_unique (gtk_object_get_type (), &type_info);
+	}
+	
+	return type;
+}
+
+ESExp *
+e_sexp_new (void)
+{
+	ESExp *f = E_SEXP ( gtk_type_new (e_sexp_get_type ()));
+
+	return f;
+}
+
+void
+e_sexp_add_function(ESExp *f, int scope, char *name, ESExpFunc *func, void *data)
+{
+	struct _ESExpSymbol *s;
+
+	g_return_if_fail(FILTER_IS_SEXP(f));
+	g_return_if_fail(name != NULL);
+
+	s = g_malloc0(sizeof(*s));
+	s->name = g_strdup(name);
+	s->f.func = func;
+	s->type = ESEXP_TERM_FUNC;
+	s->data = data;
+	g_scanner_scope_add_symbol(f->scanner, scope, s->name, s);
+}
+
+void
+e_sexp_add_ifunction(ESExp *f, int scope, char *name, ESExpIFunc *ifunc, void *data)
+{
+	struct _ESExpSymbol *s;
+
+	g_return_if_fail(FILTER_IS_SEXP(f));
+	g_return_if_fail(name != NULL);
+
+	s = g_malloc0(sizeof(*s));
+	s->name = g_strdup(name);
+	s->f.ifunc = ifunc;
+	s->type = ESEXP_TERM_IFUNC;
+	s->data = data;
+	g_scanner_scope_add_symbol(f->scanner, scope, s->name, s);
+}
+
+void
+e_sexp_add_variable(ESExp *f, int scope, char *name, ESExpTerm *value)
+{
+	struct _ESExpSymbol *s;
+
+	g_return_if_fail(FILTER_IS_SEXP(f));
+	g_return_if_fail(name != NULL);
+
+	s = g_malloc0(sizeof(*s));
+	s->name = g_strdup(name);
+	s->type = ESEXP_TERM_VAR;
+	s->data = value;
+	g_scanner_scope_add_symbol(f->scanner, scope, s->name, s);
+}
+
+void
+e_sexp_remove_symbol(ESExp *f, int scope, char *name)
+{
+	int oldscope;
+	struct _ESExpSymbol *s;
+
+	g_return_if_fail(FILTER_IS_SEXP(f));
+	g_return_if_fail(name != NULL);
+
+	oldscope = g_scanner_set_scope(f->scanner, scope);
+	s = g_scanner_lookup_symbol(f->scanner, name);
+	g_scanner_scope_remove_symbol(f->scanner, scope, name);
+	g_scanner_set_scope(f->scanner, oldscope);
+	if (s) {
+		g_free(s->name);
+		g_free(s);
+	}
+}
+
+int
+e_sexp_set_scope(ESExp *f, int scope)
+{
+	g_return_val_if_fail(FILTER_IS_SEXP(f), 0);
+
+	return g_scanner_set_scope(f->scanner, scope);
+}
+
+void
+e_sexp_input_text(ESExp *f, char *text, int len)
+{
+	g_return_if_fail(FILTER_IS_SEXP(f));
+	g_return_if_fail(text != NULL);
+
+	g_scanner_input_text(f->scanner, text, len);
+}
+
+void
+e_sexp_input_file (ESExp *f, int fd)
+{
+	g_return_if_fail(FILTER_IS_SEXP(f));
+
+	g_scanner_input_file(f->scanner, fd);
+}
+
+/* needs some error return? */
+void
+e_sexp_parse(ESExp *f)
+{
+	g_return_if_fail(FILTER_IS_SEXP(f));
+
+	f->tree = parse_list(f, FALSE);
+
+	if (f->tree)
+		parse_dump_term(f->tree, 0);
+}
+
+struct _ESExpResult *
+e_sexp_eval(ESExp *f)
+{
+	g_return_val_if_fail(FILTER_IS_SEXP(f), NULL);
+	g_return_val_if_fail(f->tree != NULL, NULL);
+
+	return e_sexp_term_eval(f, f->tree);
+}
+
+#ifdef TESTER
+int main(int argc, char **argv)
+{
+	ESExp *f;
+	char *t = "(+ \"foo\" \"\\\"\" \"bar\" \"\\\\ blah \\x \")";
+	ESExpResult *r;
+
+	gtk_init(&argc, &argv);
+
+	f = e_sexp_new();
+
+	e_sexp_add_variable(f, 0, "test", NULL);
+
+	e_sexp_input_text(f, t, strlen(t));
+	e_sexp_parse(f);
+
+	if (f->tree) {
+		parse_dump_term(f->tree, 0);
+	}
+
+	r = e_sexp_eval(f);
+	if (r) {
+		eval_dump_result(r, 0);
+	} else {
+		printf("no result?|\n");
+	}
+
+	return 0;
+}
+#endif
diff --git a/e-util/e-sexp.h b/e-util/e-sexp.h
new file mode 100644
index 0000000000..a41fdb0b58
--- /dev/null
+++ b/e-util/e-sexp.h
@@ -0,0 +1,115 @@
+/*
+  generic s-exp evaluator class
+*/
+#ifndef _E_SEXP_H
+#define _E_SEXP_H
+
+#include <glib.h>
+#include <gtk/gtk.h>
+
+#define E_SEXP(obj)         GTK_CHECK_CAST (obj, e_sexp_get_type (), ESExp)
+#define E_SEXP_CLASS(klass) GTK_CHECK_CLASS_CAST (klass, e_sexp_get_type (), ESExpClass)
+#define FILTER_IS_SEXP(obj)      GTK_CHECK_TYPE (obj, e_sexp_get_type ())
+
+typedef struct _ESExp      ESExp;
+typedef struct _ESExpClass ESExpClass;
+
+typedef struct _ESExpSymbol ESExpSymbol;
+typedef struct _ESExpResult ESExpResult;
+typedef struct _ESExpTerm ESExpTerm;
+
+typedef struct _ESExpResult *(ESExpFunc)(struct _ESExp *sexp,
+						   int argc,
+						   struct _ESExpResult **argv,
+						   void *data);
+
+typedef struct _ESExpResult *(ESExpIFunc)(struct _ESExp *sexp,
+						    int argc,
+						    struct _ESExpTerm **argv,
+						    void *data);
+enum _ESExpResultType {
+	ESEXP_RES_ARRAY_PTR=0,	/* type is a ptrarray, what it points to is implementation dependant */
+	ESEXP_RES_INT,		/* type is a number */
+	ESEXP_RES_STRING,	/* type is a pointer to a single string */
+	ESEXP_RES_BOOL,		/* boolean type */
+	ESEXP_RES_UNDEFINED	/* unknown type */
+};
+
+struct _ESExpResult {
+	enum _ESExpResultType type;
+	union {
+		GPtrArray *ptrarray;
+		int number;
+		char *string;
+		int bool;
+	} value;
+};
+
+enum _ESExpTermType {
+	ESEXP_TERM_INT	= 0,	/* integer literal */
+	ESEXP_TERM_BOOL,	/* boolean literal */
+	ESEXP_TERM_STRING,	/* string literal */
+	ESEXP_TERM_FUNC,	/* normal function, arguments are evaluated before calling */
+	ESEXP_TERM_IFUNC,	/* immediate function, raw terms are arguments */
+	ESEXP_TERM_VAR,		/* variable reference */
+};
+
+struct _ESExpSymbol {
+	int type;		/* ESEXP_TERM_FUNC or ESEXP_TERM_VAR */
+	char *name;
+	void *data;
+	union {
+		ESExpFunc *func;
+		ESExpIFunc *ifunc;
+	} f;
+};
+
+struct _ESExpTerm {
+	enum _ESExpTermType type;
+	union {
+		char *string;
+		int number;
+		int bool;
+		struct {
+			struct _ESExpSymbol *sym;
+			struct _ESExpTerm **terms;
+			int termcount;
+		} func;
+		struct _ESExpSymbol *var;
+	} value;
+};
+
+
+
+struct _ESExp {
+	GtkObject object;
+
+	GScanner *scanner;	/* for parsing text version */
+	ESExpTerm *tree;	/* root of expression tree */
+};
+
+struct _ESExpClass {
+	GtkObjectClass parent_class;
+
+};
+
+guint		e_sexp_get_type		(void);
+ESExp     *e_sexp_new			(void);
+void		e_sexp_add_function  	(ESExp *f, int scope, char *name, ESExpFunc *func, void *data);
+void		e_sexp_add_ifunction  	(ESExp *f, int scope, char *name, ESExpIFunc *func, void *data);
+void		e_sexp_add_variable  	(ESExp *f, int scope, char *name, ESExpTerm *value);
+void		e_sexp_remove_symbol	(ESExp *f, int scope, char *name);
+int		e_sexp_set_scope		(ESExp *f, int scope);
+
+void		e_sexp_input_text		(ESExp *f, char *text, int len);
+void		e_sexp_input_file		(ESExp *f, int fd);
+
+
+void		e_sexp_parse		(ESExp *f);
+ESExpResult *e_sexp_eval		(ESExp *f);
+
+ESExpResult *e_sexp_term_eval		(struct _ESExp *f, struct _ESExpTerm *t);
+ESExpResult *e_sexp_result_new	(int type);
+void		e_sexp_result_free		(struct _ESExpResult *t);
+
+#endif /* _E_SEXP_H */