Index: ossp-pkg/var/var.c
RCS File: /v/ossp/cvs/ossp-pkg/var/var.c,v
rcsdiff -q -kk '-r1.69' '-r1.70' -u '/v/ossp/cvs/ossp-pkg/var/var.c,v' 2>/dev/null
--- var.c	2002/02/28 12:40:01	1.69
+++ var.c	2002/02/28 20:28:14	1.70
@@ -58,6 +58,16 @@
 #define VAR_RC(rv) (rv)
 #endif /* WITH_EX */
 
+#ifndef NUL
+#define NUL '\0'
+#endif
+
+/*
+**
+**  ==== INTERNAL DATA STRUCTURES ====
+**
+*/
+
 typedef char char_class_t[256]; /* 256 == 2 ^ sizeof(unsigned char)*8 */
 
 /* the external context structure */
@@ -71,7 +81,7 @@
 /* the internal expansion context structure */
 typedef struct {
     int            force_expand;
-} var_expand_t;
+} var_parse_t;
 
 /* the default syntax configuration */
 static const var_syntax_t var_syntax_default = {
@@ -85,7 +95,11 @@
     "a-zA-Z0-9_"  /* name_chars */
 };
 
-/* Routines for manipulation of token buffers. */
+/*
+**
+**  ==== TOKEN BUFFER FUNCTIONS ====
+**
+*/
 
 #define TOKENBUF_INITIAL_BUFSIZE 64
 
@@ -122,7 +136,7 @@
     buf->begin = p;
     buf->end = p + len;
     buf->buffer_size = len + 1;
-    *((char *)(buf->end)) = '\0';
+    *((char *)(buf->end)) = NUL;
     return 1;
 }
 
@@ -176,7 +190,7 @@
     /* Append the data at the end of the current buffer. */
     memcpy((char *)output->end, data, len);
     output->end += len;
-    *((char *)output->end) = '\0';
+    *((char *)output->end) = NUL;
     return 1;
 }
 
@@ -202,7 +216,11 @@
     return num;
 }
 
-/* Routines for the expansion of quoted-pair expressions. */
+/*
+**
+**  ==== ESCAPE SEQUENCE FUNCTIONS ====
+**
+*/
 
 static void expand_range(char a, char b, char_class_t class)
 {
@@ -224,8 +242,8 @@
     /* Walk through the class description and set the appropriate
        entries in the array. */
 
-    while (*desc != '\0') {
-        if (desc[1] == '-' && desc[2] != '\0') {
+    while (*desc != NUL) {
+        if (desc[1] == '-' && desc[2] != NUL) {
             if (desc[0] > desc[2])
                 return VAR_ERR_INCORRECT_CLASS_SPEC;
             expand_range(desc[0], desc[2], class);
@@ -341,95 +359,115 @@
         return expand_simple_hex(src, dst, end);
 }
 
-/* The recursive-descent parser for variable expressions. */
-
-static int variable(const char *begin, const char *end,
-                    const var_syntax_t *config, const char_class_t nameclass,
-                    var_cb_value_t lookup, void *lookup_context,
-                    int force_expand, tokenbuf_t *result, int index_mark,
-                    int* rel_lookup_flag);
-static int command(const char *begin, const char *end,
-                   const var_syntax_t *config, const char_class_t nameclass,
-                   var_cb_value_t lookup, void *lookup_context, int force_expand,
-                   tokenbuf_t *data, int index_mark, int* rel_lookup_flag);
-static int num_exp(const char *begin, const char *end, int index_mark,
-                   int* result, int* failed, int* rel_lookup_flag,
-                   const var_syntax_t *config,
-                   const char_class_t nameclass,
-                   var_cb_value_t lookup, void* lookup_context);
-
-static int text(const char *begin, const char *end, char delim_init,
-                char index_open, char index_close, char escape)
+/* 
+**
+**  ==== RECURSIVE-DESCEND VARIABLE EXPANSION PARSER ====
+**
+*/
+
+/* forward declarations */
+static int parse_variable(var_t *var, var_parse_t *ctx, const char *begin, const char *end, int force_expand, tokenbuf_t *result, int index_this, int* rel_lookup_flag);
+static int parse_command (var_t *var, var_parse_t *ctx, const char *begin, const char *end, int force_expand, tokenbuf_t *data, int index_this, int* rel_lookup_flag);
+static int parse_num_exp (var_t *var, var_parse_t *ctx, const char *begin, const char *end, int index_this, int* result, int* failed, int* rel_lookup_flag);
+
+/* parse plain text */
+static int 
+parse_text(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end)
 {
     const char *p;
 
-    for (p = begin; p != end; ++p) {
-        if (*p == escape) {
-            if (++p == end)
+    /* parse until delim_init (variable construct) 
+       or index_open (loop construct) is found */
+    for (p = begin; p != end; p++) {
+        if (*p == var->syntax.escape) {
+            p++; /* skip next character */
+            if (p == end)
                 return VAR_ERR_INCOMPLETE_QUOTED_PAIR;
         }
-        else if (*p == delim_init)
+        else if (*p == var->syntax.delim_init)
             break;
-        else if (index_open && (*p == index_open || *p == index_close))
+        else if (   var->syntax.index_open != NUL
+                 && (   *p == var->syntax.index_open 
+                     || *p == var->syntax.index_close))
             break;
     }
-    return p - begin;
+    return (p - begin);
 }
 
-static int varname(const char *begin, const char *end,
-                   const char_class_t nameclass)
+/* parse variable name */
+static int 
+parse_varname(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end)
 {
     const char *p;
 
-    for (p = begin; p != end && nameclass[(int) *p]; p++)
+    /* parse as long as name class characters are found */
+    for (p = begin; p != end && var->syntax_nameclass[(int)(*p)]; p++)
         ;
-    return p - begin;
+    return (p - begin);
 }
 
-static int number(const char *begin, const char *end)
+/* parse number */
+static int 
+parse_number(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end)
 {
     const char *p;
 
-    for (p = begin; p != end && isdigit((int)*p); p++)
+    /* parse as long as digits are found */
+    for (p = begin; p != end && isdigit((int)(*p)); p++)
         ;
-    return p - begin;
+    return (p - begin);
 }
 
-static int substext(const char *begin, const char *end,
-                    const var_syntax_t *config)
+/* parse substitution text */
+static int 
+parse_substext(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end)
 {
     const char *p;
 
-    for (p = begin; p != end && *p != config->delim_init && *p != '/'; p++) {
-        if (*p == config->escape) {
+    /* parse until delim_init or '/' */
+    for (p = begin; p != end && *p != var->syntax.delim_init && *p != '/'; p++) {
+        if (*p == var->syntax.escape) {
             if (p + 1 == end)
                 return VAR_ERR_INCOMPLETE_QUOTED_PAIR;
             p++;
         }
     }
-    return p - begin;
+    return (p - begin);
 }
 
-static int exptext(const char *begin, const char *end,
-                   const var_syntax_t *config)
+/* parse expression? XXX text */
+static int 
+parse_exptext(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end)
 {
     const char *p;
 
-    for (p = begin;
-            p != end
-         && *p != config->delim_init
-         && *p != config->delim_close
-         && *p != ':'; p++) {
-        if (*p == config->escape) {
+    /* parse until delim_init or delim_close or ':' */
+    for (p = begin;     p != end
+                    && *p != var->syntax.delim_init
+                    && *p != var->syntax.delim_close
+                    && *p != ':'; p++) {
+        if (*p == var->syntax.escape) {
             if (p + 1 == end)
                 return VAR_ERR_INCOMPLETE_QUOTED_PAIR;
             p++;
         }
     }
-    return p - begin;
+    return (p - begin);
 }
 
-static int num_exp_read_int(const char **begin, const char *end)
+/* convert a string into a decimal number */
+static int 
+convert_num_exp_read_int(const char **begin, const char *end)
 {
     int num = 0;
 
@@ -441,24 +479,26 @@
     return num;
 }
 
-static int num_exp_read_operand(const char *begin, const char *end, int index_mark,
-                                int *result, int *failed, int *rel_lookup_flag,
-                                const var_syntax_t *config,
-                                const char_class_t nameclass,
-                                var_cb_value_t lookup, void *lookup_context)
+/* parse number expression operand */
+static int 
+parse_num_exp_operand(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end, 
+    int index_this, int *result, int *failed, int *rel_lookup_flag)
 {
-    const char* p = begin;
+    const char *p;
     tokenbuf_t tmp;
     int rc;
 
+    p = begin;
     tokenbuf_init(&tmp);
 
     if (begin == end)
         return VAR_ERR_INCOMPLETE_INDEX_SPEC;
 
     if (*p == '(') {
-        rc = num_exp(++p, end, index_mark, result, failed,
-                     rel_lookup_flag, config, nameclass, lookup, lookup_context);
+        rc = parse_num_exp(var, ctx, ++p, end, index_this, result, failed,
+                     rel_lookup_flag);
         if (rc < 0)
             return rc;
         p += rc;
@@ -468,13 +508,13 @@
             return VAR_ERR_UNCLOSED_BRACKET_IN_INDEX;
         ++p;
     }
-    else if (*p == config->delim_init) {
-        rc = variable(p, end, config, nameclass, lookup,
-                      lookup_context, 1, &tmp, index_mark, rel_lookup_flag);
+    else if (*p == var->syntax.delim_init) {
+        rc = parse_variable(var, ctx, p, end, 
+                            1, &tmp, index_this, rel_lookup_flag);
         if (rc == VAR_ERR_UNDEFINED_VARIABLE) {
             *failed = 1;
-            rc = variable(p, end, config, nameclass, lookup,
-                          lookup_context, 0, &tmp, index_mark, rel_lookup_flag);
+            rc = parse_variable(var, ctx, p, end, 
+                                0, &tmp, index_this, rel_lookup_flag);
             if (rc < 0)
                 return rc;
             p += rc;
@@ -484,25 +524,25 @@
             if (rc < 0)
                 return rc;
             p += rc;
-            rc = num_exp(tmp.begin, tmp.end, index_mark, result,
-                         failed, rel_lookup_flag, config, nameclass, lookup, lookup_context);
+            rc = parse_num_exp(var, ctx, tmp.begin, tmp.end, index_this, result,
+                         failed, rel_lookup_flag );
             tokenbuf_free(&tmp);
             if (rc < 0)
                 return rc;
         }
     }
-    else if (config->index_mark && *p == config->index_mark) {
+    else if (var->syntax.index_mark && *p == var->syntax.index_mark) {
         p++;
-        *result = index_mark;
+        *result = index_this;
         (*rel_lookup_flag)++;
     }
     else if (isdigit(*p)) {
-        *result = num_exp_read_int(&p, end);
+        *result = convert_num_exp_read_int(&p, end);
     }
     else if (*p == '+') {
         if (end - p > 1 && isdigit(p[1])) {
             p++;
-            *result = num_exp_read_int(&p, end);
+            *result = convert_num_exp_read_int(&p, end);
         }
         else
             return VAR_ERR_INVALID_CHAR_IN_INDEX_SPEC;
@@ -510,7 +550,7 @@
     else if (*p == '-') {
         if (end - p > 1 && isdigit(p[1])) {
             p++;
-            *result = num_exp_read_int(&p, end);
+            *result = convert_num_exp_read_int(&p, end);
             *result = 0 - *result;
         }
         else
@@ -519,14 +559,15 @@
     else
         return VAR_ERR_INVALID_CHAR_IN_INDEX_SPEC;
 
-    return p - begin;
+    return (p - begin);
 }
 
-static int num_exp(const char *begin, const char *end, int index_mark,
-                   int *result, int *failed, int *rel_lookup_flag,
-                   const var_syntax_t *config,
-                   const char_class_t nameclass,
-                   var_cb_value_t lookup, void *lookup_context)
+static int 
+parse_num_exp(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end, 
+    int index_this,
+    int *result, int *failed, int *rel_lookup_flag)
 {
     const char *p = begin;
     char operator;
@@ -536,9 +577,8 @@
     if (begin == end)
         return VAR_ERR_INCOMPLETE_INDEX_SPEC;
 
-    rc = num_exp_read_operand(p, end, index_mark, result,
-                              failed, rel_lookup_flag, config, nameclass,
-                              lookup, lookup_context);
+    rc = parse_num_exp_operand(var, ctx, p, end, index_this, result,
+                              failed, rel_lookup_flag);
     if (rc < 0)
         return rc;
     p += rc;
@@ -546,8 +586,8 @@
     while (p != end) {
         if (*p == '+' || *p == '-') {
             operator = *p++;
-            rc = num_exp(p, end, index_mark, &right, failed,
-                         rel_lookup_flag, config, nameclass, lookup, lookup_context);
+            rc = parse_num_exp(var, ctx, p, end, index_this, &right, failed,
+                         rel_lookup_flag);
             if (rc < 0)
                 return rc;
             p += rc;
@@ -558,8 +598,8 @@
         }
         else if (*p == '*' || *p == '/' || *p == '%') {
             operator = *p++;
-            rc = num_exp_read_operand(p, end, index_mark, &right, failed,
-                                      rel_lookup_flag, config, nameclass, lookup, lookup_context);
+            rc = parse_num_exp_operand(var, ctx, p, end, index_this, &right, failed,
+                                      rel_lookup_flag);
             if (rc < 0)
                 return rc;
             p += rc;
@@ -593,12 +633,13 @@
     return p - begin;
 }
 
-static int expression(const char *begin, const char *end,
-                      const var_syntax_t *config,
-                      const char_class_t nameclass, var_cb_value_t lookup,
-                      void *lookup_context, int force_expand,
-                      tokenbuf_t *result, int index_mark, int *rel_lookup_flag)
-    {
+static int 
+parse_expression(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end,
+    int force_expand,
+    tokenbuf_t *result, int index_this, int *rel_lookup_flag)
+{
     const char *p = begin;
     const char *data;
     size_t len, buffer_size;
@@ -616,7 +657,7 @@
 
     /* Expect STARTDELIM. */
 
-    if (p == end || *p != config->delim_open)
+    if (p == end || *p != var->syntax.delim_open)
         return 0;
 
     if (++p == end)
@@ -626,7 +667,7 @@
        an arbitrary number of VARNAMEs and VARIABLEs. */
 
     do {
-        rc = varname(p, end, nameclass);
+        rc = parse_varname(var, ctx, p, end);
         if (rc < 0)
             goto error_return;
         if (rc > 0) {
@@ -637,8 +678,8 @@
             p += rc;
         }
 
-        rc = variable(p, end, config, nameclass, lookup, lookup_context,
-                      force_expand, &tmp, index_mark, rel_lookup_flag);
+        rc = parse_variable(var, ctx, p, end, 
+                      force_expand, &tmp, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         if (rc > 0) {
@@ -673,9 +714,9 @@
 
     /* If the next token is START-INDEX, read the index specification. */
 
-    if (config->index_open && *p == config->index_open) {
-        rc = num_exp(++p, end, index_mark, &idx, &failed,
-                     rel_lookup_flag, config, nameclass, lookup, lookup_context);
+    if (var->syntax.index_open && *p == var->syntax.index_open) {
+        rc = parse_num_exp(var, ctx, ++p, end, index_this, &idx, &failed,
+                     rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         if (rc == 0) {
@@ -688,7 +729,7 @@
             rc = VAR_ERR_INCOMPLETE_INDEX_SPEC;
             goto error_return;
         }
-        if (*p != config->index_close) {
+        if (*p != var->syntax.index_close) {
             rc = VAR_ERR_INVALID_CHAR_IN_INDEX_SPEC;
             goto error_return;
         }
@@ -698,7 +739,7 @@
     /* Now we have the name of the variable stored in "name". The next
        token here must either be an END-DELIM or a ':'. */
 
-    if (p == end || (*p != config->delim_close && *p != ':')) {
+    if (p == end || (*p != var->syntax.delim_close && *p != ':')) {
         rc = VAR_ERR_INCOMPLETE_VARIABLE_SPEC;
         goto error_return;
     }
@@ -712,7 +753,7 @@
         result->buffer_size = 0;
     }
     else {
-        rc = (*lookup) (NULL, lookup_context, name.begin, name.end - name.begin, idx,
+        rc = (*var->cb_value_fct) (var, var->cb_value_ctx, name.begin, name.end - name.begin, idx,
                         &data, &len, &buffer_size);
         if (rc == VAR_ERR_UNDEFINED_VARIABLE) {
             /* The variable is undefined. What we'll do now depends on the
@@ -748,13 +789,13 @@
         while (p != end && *p == ':') {
             p++;
             if (!failed)
-                rc = command(p, end, config, nameclass, lookup,
-                             lookup_context, force_expand, result,
-                             index_mark, rel_lookup_flag);
+                rc = parse_command(var, ctx, p, end, 
+                             force_expand, result,
+                             index_this, rel_lookup_flag);
             else
-                rc = command(p, end, config, nameclass, lookup,
-                             lookup_context, force_expand, &tmp,
-                             index_mark, rel_lookup_flag);
+                rc = parse_command(var, ctx, p, end, 
+                             force_expand, &tmp,
+                             index_this, rel_lookup_flag);
             if (rc < 0)
                 goto error_return;
             p += rc;
@@ -762,7 +803,7 @@
                 result->end += rc;
         }
 
-        if (p == end || *p != config->delim_close) {
+        if (p == end || *p != var->syntax.delim_close) {
             rc = VAR_ERR_INCOMPLETE_VARIABLE_SPEC;
             goto error_return;
         }
@@ -786,11 +827,13 @@
     return rc;
 }
 
-static int variable(const char *begin, const char *end,
-                    const var_syntax_t *config, const char_class_t nameclass,
-                    var_cb_value_t lookup, void *lookup_context,
-                    int force_expand, tokenbuf_t *result, int index_mark,
-                    int *rel_lookup_flag)
+static int 
+parse_variable(
+    var_t *var, 
+    var_parse_t *ctx,
+    const char *begin, const char *end,
+    int force_expand, tokenbuf_t *result, int index_this,
+    int *rel_lookup_flag)
 {
     const char *p = begin;
     const char *data;
@@ -804,7 +847,7 @@
 
     /* Expect VARINIT. */
 
-    if (p == end || *p != config->delim_init)
+    if (p == end || *p != var->syntax.delim_init)
         return 0;
 
     if (++p == end)
@@ -813,11 +856,11 @@
     /* Try to read the variable name. If that fails, we're parsing a
        complex expression. */
 
-    rc = varname(p, end, nameclass);
+    rc = parse_varname(var, ctx, p, end);
     if (rc < 0)
         return rc;
     if (rc > 0) {
-        rc2 = (*lookup)(NULL, lookup_context, p, rc, 0, &data, &len, &buffer_size);
+        rc2 = (*var->cb_value_fct)(var, var->cb_value_ctx, p, rc, 0, &data, &len, &buffer_size);
         if (rc2 == VAR_ERR_UNDEFINED_VARIABLE && !force_expand) {
             result->begin = begin;
             result->end = begin + 1 + rc;
@@ -834,19 +877,20 @@
 
     /* OK, we're dealing with a complex expression here. */
 
-    rc = expression(p, end, config, nameclass, lookup, lookup_context,
-                    force_expand, result, index_mark, rel_lookup_flag);
+    rc = parse_expression(var, ctx, p, end, 
+                    force_expand, result, index_this, rel_lookup_flag);
     if (rc > 0)
         rc++;
     return rc;
 }
 
-static int exptext_or_variable(const char *begin, const char *end,
-                               const var_syntax_t *config,
-                               const char_class_t nameclass, var_cb_value_t lookup,
-                               void *lookup_context, int force_expand,
-                               tokenbuf_t *result, int index_mark,
-                               int *rel_lookup_flag)
+static int 
+parse_exptext_or_variable(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end,
+    int force_expand,
+    tokenbuf_t *result, int index_this,
+    int *rel_lookup_flag)
 {
     const char *p = begin;
     tokenbuf_t tmp;
@@ -859,7 +903,7 @@
         return 0;
 
     do {
-        rc = exptext(p, end, config);
+        rc = parse_exptext(var, ctx, p, end);
         if (rc < 0)
             goto error_return;
         if (rc > 0) {
@@ -870,8 +914,8 @@
             p += rc;
         }
 
-        rc = variable(p, end, config, nameclass, lookup, lookup_context,
-                      force_expand, &tmp, index_mark, rel_lookup_flag);
+        rc = parse_variable(var, ctx, p, end, 
+                      force_expand, &tmp, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         if (rc > 0) {
@@ -893,12 +937,13 @@
     return rc;
 }
 
-static int substext_or_variable(const char *begin, const char *end,
-                                const var_syntax_t *config,
-                                const char_class_t nameclass, var_cb_value_t lookup,
-                                void *lookup_context, int force_expand,
-                                tokenbuf_t *result, int index_mark,
-                                int *rel_lookup_flag)
+static int 
+parse_substext_or_variable(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end,
+    int force_expand,
+    tokenbuf_t *result, int index_this,
+    int *rel_lookup_flag)
 {
     const char *p = begin;
     tokenbuf_t tmp;
@@ -911,7 +956,7 @@
         return 0;
 
     do {
-        rc = substext(p, end, config);
+        rc = parse_substext(var, ctx, p, end);
         if (rc < 0)
             goto error_return;
         if (rc > 0) {
@@ -922,8 +967,8 @@
             p += rc;
         }
 
-        rc = variable(p, end, config, nameclass, lookup, lookup_context,
-                      force_expand, &tmp, index_mark, rel_lookup_flag);
+        rc = parse_variable(var, ctx, p, end, 
+                      force_expand, &tmp, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         if (rc > 0) {
@@ -945,7 +990,7 @@
     return rc;
 }
 
-static int expand_class_description(tokenbuf_t *src, tokenbuf_t *dst)
+static int parse_class_description(tokenbuf_t *src, tokenbuf_t *dst)
 {
     unsigned char c, d;
     const char *p = src->begin;
@@ -979,9 +1024,9 @@
     tokenbuf_init(&srcclass);
     tokenbuf_init(&dstclass);
 
-    if ((rc = expand_class_description(search, &srcclass)) != VAR_OK)
+    if ((rc = parse_class_description(search, &srcclass)) != VAR_OK)
         goto error_return;
-    if ((rc = expand_class_description(replace, &dstclass)) != VAR_OK)
+    if ((rc = parse_class_description(replace, &dstclass)) != VAR_OK)
         goto error_return;
 
     if (srcclass.begin == srcclass.end) {
@@ -1067,7 +1112,7 @@
     return VAR_OK;
 }
 
-static int expand_regex_replace(const char *data, tokenbuf_t *orig,
+static int parse_regex_replace(const char *data, tokenbuf_t *orig,
                                 regmatch_t *pmatch, tokenbuf_t *expanded)
 {
     const char *p = orig->begin;
@@ -1219,7 +1264,7 @@
                 tokenbuf_append(&tmp, p, mydata.end - p);
                 break;
             } else {
-                rc = expand_regex_replace(p, replace, pmatch, &myreplace);
+                rc = parse_regex_replace(p, replace, pmatch, &myreplace);
                 if (rc != VAR_OK) {
                     regfree(&preg);
                     tokenbuf_free(&tmp);
@@ -1379,10 +1424,12 @@
     return VAR_OK;
 }
 
-static int command(const char *begin, const char *end,
-                   const var_syntax_t *config, const char_class_t nameclass,
-                   var_cb_value_t lookup, void *lookup_context, int force_expand,
-                   tokenbuf_t *data, int index_mark, int *rel_lookup_flag)
+static int 
+parse_command(
+    var_t *var, var_parse_t *ctx,
+    const char *begin, const char *end,
+    int force_expand,
+    tokenbuf_t *data, int index_this, int *rel_lookup_flag)
 {
     const char *p = begin;
     tokenbuf_t tmptokbuf;
@@ -1438,7 +1485,7 @@
 
     case 'o':                   /* Cut out substrings. */
         ++p;
-        rc = number(p, end);
+        rc = parse_number(var, ctx, p, end);
         if (rc == 0) {
             rc = VAR_ERR_MISSING_START_OFFSET;
             goto error_return;
@@ -1459,7 +1506,7 @@
             goto error_return;
         }
 
-        rc = number(p, end);
+        rc = parse_number(var, ctx, p, end);
         number2.begin = p;
         number2.end = p + rc;
         number2.buffer_size = 0;
@@ -1486,9 +1533,9 @@
 
     case '-':                   /* Substitute parameter if data is empty. */
         p++;
-        rc = exptext_or_variable(p, end, config, nameclass, lookup,
-                                 lookup_context, force_expand, &tmptokbuf,
-                                 index_mark, rel_lookup_flag);
+        rc = parse_exptext_or_variable(var, ctx, p, end, 
+                                 force_expand, &tmptokbuf,
+                                 index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         if (rc == 0) {
@@ -1504,8 +1551,8 @@
 
     case '*':                   /* Return "" if data is not empty, parameter otherwise. */
         p++;
-        rc = exptext_or_variable(p, end, config, nameclass, lookup,
-                                 lookup_context, force_expand, &tmptokbuf, index_mark, rel_lookup_flag);
+        rc = parse_exptext_or_variable(var, ctx, p, end, 
+                                 force_expand, &tmptokbuf, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         if (rc == 0) {
@@ -1527,8 +1574,8 @@
 
     case '+':                   /* Substitute parameter if data is not empty. */
         p++;
-        rc = exptext_or_variable(p, end, config, nameclass, lookup,
-                                 lookup_context, force_expand, &tmptokbuf, index_mark, rel_lookup_flag);
+        rc = parse_exptext_or_variable(var, ctx, p, end, 
+                                 force_expand, &tmptokbuf, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         if (rc == 0) {
@@ -1549,8 +1596,8 @@
             return VAR_ERR_MALFORMATTED_REPLACE;
         p++;
 
-        rc = substext_or_variable(p, end, config, nameclass, lookup,
-                                  lookup_context, force_expand, &search, index_mark, rel_lookup_flag);
+        rc = parse_substext_or_variable(var, ctx, p, end, 
+                                  force_expand, &search, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         p += rc;
@@ -1561,8 +1608,8 @@
         }
         p++;
 
-        rc = substext_or_variable(p, end, config, nameclass, lookup,
-                                  lookup_context, force_expand, &replace, index_mark, rel_lookup_flag);
+        rc = parse_substext_or_variable(var, ctx, p, end, 
+                                  force_expand, &replace, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         p += rc;
@@ -1573,7 +1620,7 @@
         }
         p++;
 
-        rc = exptext(p, end, config);
+        rc = parse_exptext(var, ctx, p, end);
         if (rc < 0)
             goto error_return;
         flags.begin = p;
@@ -1595,8 +1642,8 @@
             return VAR_ERR_MALFORMATTED_TRANSPOSE;
         p++;
 
-        rc = substext_or_variable(p, end, config, nameclass, lookup,
-                                  lookup_context, force_expand, &search, index_mark, rel_lookup_flag);
+        rc = parse_substext_or_variable(var, ctx, p, end, 
+                                  force_expand, &search, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         p += rc;
@@ -1607,8 +1654,8 @@
         }
         p++;
 
-        rc = substext_or_variable(p, end, config, nameclass, lookup,
-                                  lookup_context, force_expand, &replace, index_mark, rel_lookup_flag);
+        rc = parse_substext_or_variable(var, ctx, p, end, 
+                                  force_expand, &replace, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         p += rc;
@@ -1634,7 +1681,7 @@
             return VAR_ERR_MALFORMATTED_PADDING;
         p++;
 
-        rc = number(p, end);
+        rc = parse_number(var, ctx, p, end);
         if (rc == 0) {
             rc = VAR_ERR_MISSING_PADDING_WIDTH;
             goto error_return;
@@ -1650,8 +1697,8 @@
         }
         p++;
 
-        rc = substext_or_variable(p, end, config, nameclass, lookup,
-                                  lookup_context, force_expand, &replace, index_mark, rel_lookup_flag);
+        rc = parse_substext_or_variable(var, ctx, p, end, 
+                                  force_expand, &replace, index_this, rel_lookup_flag);
         if (rc < 0)
             goto error_return;
         p += rc;
@@ -1700,57 +1747,30 @@
     return rc;
 }
 
-struct wrapper_context {
-    var_cb_value_t lookup;
-    void    *context;
-    int     *rel_lookup_flag;
-};
-
-static int lookup_wrapper(var_t *var, void *context,
-                          const char *name, size_t name_len, int idx,
-                          const char **data, size_t *data_len,
-                          size_t *buffer_size)
+/* expand the loop limits */
+static var_rc_t 
+parse_looplimits(
+    var_t *var,
+    var_parse_t *ctx,
+    const char *begin, const char *end,
+    int* start, int* step, int* stop, int* open_end)
 {
-    static char buf[1];
-    struct wrapper_context *wcon = context;
-    int rc;
-
-    rc = (*wcon->lookup)(NULL, wcon->context, name, name_len,
-                         idx, data, data_len, buffer_size);
-    if (rc == VAR_ERR_UNDEFINED_VARIABLE) {
-        (*wcon->rel_lookup_flag)--;
-        *data = buf;
-        *data_len = 0;
-        *buffer_size = 0;
-        return VAR_OK;
-    }
-    return rc;
-}
-
-static var_rc_t loop_limits(const char *begin, const char *end,
-			    const var_syntax_t *config,
-                            const char_class_t nameclass,
-                            var_cb_value_t lookup, void* lookup_context,
-                            int* start, int* step, int* stop, int* open_end)
-    {
-    const char* p = begin;
+    const char *p;
     int rc;
     int failed;
     int dummy;
 
+    p = begin;
     if (begin == end)
         return 0;
-
-    if (*p != config->delim_open)
+    if (*p != var->syntax.delim_open)
         return 0;
     else
-        ++p;
+        p++;
 
     /* Read start value for the loop. */
-
     failed = 0;
-    rc = num_exp(p, end, 0, start, &failed, &dummy,
-                 config, nameclass, lookup, lookup_context);
+    rc = parse_num_exp(var, ctx, p, end, 0, start, &failed, &dummy);
     if (rc == VAR_ERR_INVALID_CHAR_IN_INDEX_SPEC)
         *start = 0;          /* use default */
     else if (rc < 0)
@@ -1763,13 +1783,11 @@
     if (*p != ',')
         return VAR_ERR_INVALID_CHAR_IN_LOOP_LIMITS;
     else
-        ++p;
+        p++;
 
     /* Read step value for the loop. */
-
     failed = 0;
-    rc = num_exp(p, end, 0, step, &failed, &dummy,
-                 config, nameclass, lookup, lookup_context);
+    rc = parse_num_exp(var, ctx, p, end, 0, step, &failed, &dummy);
     if (rc == VAR_ERR_INVALID_CHAR_IN_INDEX_SPEC)
         *step = 1;          /* use default */
     else if (rc < 0)
@@ -1778,14 +1796,11 @@
         p += rc;
     if (failed)
         return VAR_ERR_UNDEFINED_VARIABLE;
-
-    if (*p != ',')
-        {
-        if (*p != config->delim_close)
+    if (*p != ',') {
+        if (*p != var->syntax.delim_close)
             return VAR_ERR_INVALID_CHAR_IN_LOOP_LIMITS;
-        else
-            {
-            ++p;
+        else {
+            p++;
             *stop = *step;
             *step = 1;
             if (rc > 0)
@@ -1793,43 +1808,77 @@
             else
                 *open_end = 1;
             return p - begin;
-            }
         }
+    }
     else
-        ++p;
+        p++;
 
     /* Read stop value for the loop. */
-
     failed = 0;
-    rc = num_exp(p, end, 0, stop, &failed, &dummy,
-                 config, nameclass, lookup, lookup_context);
-    if (rc == VAR_ERR_INVALID_CHAR_IN_INDEX_SPEC)
-        {
-        *stop = 0;          /* use default */
+    rc = parse_num_exp(var, ctx, p, end, 0, stop, &failed, &dummy);
+    if (rc == VAR_ERR_INVALID_CHAR_IN_INDEX_SPEC) {
+        *stop = 0;  /* use default */
         *open_end = 1;
-        }
+    }
     else if (rc < 0)
         return rc;
-    else
-        {
+    else {
         *open_end = 0;
         p += rc;
-        }
+    }
     if (failed)
         return VAR_ERR_UNDEFINED_VARIABLE;
-
-    if (*p != config->delim_close)
+    if (*p != var->syntax.delim_close)
         return VAR_ERR_INVALID_CHAR_IN_LOOP_LIMITS;
 
     return ++p - begin;
+}
+
+/* callback wrapper context */
+typedef struct {
+    var_cb_value_t cb_value_fct;
+    void          *cb_value_ctx;
+    int           *rel_lookup_flag;
+} var_wrapper_t;
+
+/* callback wrapper function */
+static int 
+lookup_wrapper(
+    var_t *var, void *ctx,
+    const char  *var_ptr, size_t  var_len, int     var_idx,
+    const char **val_ptr, size_t *val_len, size_t *val_size)
+{
+    char buf[1];
+    var_wrapper_t *wcon = (var_wrapper_t *)ctx;
+    int rc;
+
+    /* pass through to original callback */
+    rc = (*wcon->cb_value_fct)(var, wcon->cb_value_ctx,
+                               var_ptr, var_len, var_idx, 
+                               val_ptr, val_len, val_size);
+
+    /* convert undefined variable into empty variable */
+    if (rc == VAR_ERR_UNDEFINED_VARIABLE) {
+        (*wcon->rel_lookup_flag)--;
+        buf[0] = NUL;
+        *val_ptr  = buf;
+        *val_len  = 0;
+        *val_size = 0;
+        return VAR_OK;
     }
 
-static var_rc_t input(const char *begin, const char *end,
-                      const var_syntax_t *config,
-                      const char_class_t nameclass, var_cb_value_t lookup,
-                      void *lookup_context, int force_expand,
-                      tokenbuf_t *output, int index_mark,
-                      size_t recursion_level, int *rel_lookup_flag)
+    return rc;
+}
+
+/* expand input in general */
+static var_rc_t 
+parse_input(
+    var_t *var,
+    var_parse_t *ctx,
+    const char *begin, const char *end,
+    int force_expand,
+    tokenbuf_t *output, int index_this,
+    size_t recursion_level, int *rel_lookup_flag)
 {
     const char *p = begin;
     int rc, rc2;
@@ -1837,7 +1886,7 @@
     int start, step, stop, open_end;
     int i;
     int output_backup;
-    struct wrapper_context wcon;
+    var_wrapper_t wcon;
     int my_rel_lookup_flag;
     int original_rel_lookup_state;
     int loop_limit_length;
@@ -1850,12 +1899,9 @@
     }
 
     do {
-        if (begin != end && config->index_open && *begin == config->index_open) {
+        if (begin != end && var->syntax.index_open && *begin == var->syntax.index_open) {
             original_rel_lookup_state = *rel_lookup_flag;
             loop_limit_length = -1;
-            wcon.lookup = lookup;
-            wcon.context = lookup_context;
-            wcon.rel_lookup_flag = rel_lookup_flag;
             begin++;
             start = 0;
             step  = 1;
@@ -1870,34 +1916,41 @@
                  i += step) {
                 *rel_lookup_flag = original_rel_lookup_state;
                 output_backup = output->end - output->begin;
-                rc = input(begin, end, config, nameclass, &lookup_wrapper,
-                           &wcon, 1, output, i, recursion_level+1, rel_lookup_flag);
+
+                /* activate callback wrapper */
+                wcon.cb_value_fct    = var->cb_value_fct;
+                wcon.cb_value_ctx    = var->cb_value_ctx;
+                wcon.rel_lookup_flag = rel_lookup_flag;
+                var->cb_value_fct    = lookup_wrapper;
+                var->cb_value_ctx    = &wcon;
+
+                rc = parse_input(var, ctx, begin, end, 
+                                 1, output, i, recursion_level+1, rel_lookup_flag);
+
+                /* deactivate callback wrapper */
+                var->cb_value_fct = wcon.cb_value_fct;
+                var->cb_value_ctx = wcon.cb_value_ctx;
+
                 if (rc < 0)
                     goto error_return;
-                if (begin[rc] != config->index_close) {
+                if (begin[rc] != var->syntax.index_close) {
                     rc = VAR_ERR_UNTERMINATED_LOOP_CONSTRUCT;
                     goto error_return;
                 }
-                if (loop_limit_length < 0)
-                    {
-                    rc2 = loop_limits(begin + rc + 1, end, config, nameclass,
-                                      lookup, lookup_context, &start, &step,
-                                      &stop, &open_end);
+                if (loop_limit_length < 0) {
+                    rc2 = parse_looplimits(var, ctx, begin + rc + 1, end, 
+                                            &start, &step,
+                                            &stop, &open_end);
                     if (rc2 < 0)
-                        {
                         goto error_return;
-                        }
                     else if (rc2 == 0)
-                        {
                         loop_limit_length = 0;
-                        }
-                    else if (rc2 > 0)
-                        {
+                    else if (rc2 > 0) {
                         loop_limit_length = rc2;
                         output->end = output->begin + output_backup;
                         goto re_loop;
-                        }
                     }
+                }
             }
             if (open_end)
                 output->end = output->begin + output_backup;
@@ -1909,8 +1962,7 @@
             continue;
         }
 
-        rc = text(begin, end, config->delim_init, config->index_open,
-                  config->index_close, config->escape);
+        rc = parse_text(var, ctx, begin, end);
         if (rc > 0) {
             if (!tokenbuf_append(output, begin, rc)) {
                 rc = VAR_ERR_OUT_OF_MEMORY;
@@ -1921,9 +1973,9 @@
         } else if (rc < 0)
             goto error_return;
 
-        rc = variable(begin, end, config, nameclass, lookup,
-                      lookup_context, force_expand, &result,
-                      index_mark, rel_lookup_flag);
+        rc = parse_variable(var, ctx, begin, end, 
+                             force_expand, &result,
+                             index_this, rel_lookup_flag);
         if (rc > 0) {
             if (!tokenbuf_append(output, result.begin, result.end - result.begin)) {
                 rc = VAR_ERR_OUT_OF_MEMORY;
@@ -1952,7 +2004,11 @@
     return rc;
 }
 
-/* ------------------------------------------------------------------ */
+/* 
+**
+**  ==== APPLICATION PROGRAMMING INTERFACE (API) ====
+**
+*/
 
 var_rc_t 
 var_create(
@@ -2088,7 +2144,7 @@
         } else
             *dst++ = *src++;
     }
-    *dst = '\0';
+    *dst = NUL;
     return VAR_OK;
 }
 
@@ -2099,7 +2155,7 @@
     char **dst_ptr, size_t *dst_len, 
     int force_expand)
 {
-    var_expand_t ctx;
+    var_parse_t ctx;
     tokenbuf_t output;
     var_rc_t rc;
 
@@ -2116,10 +2172,9 @@
 
     /* call the parsing */
     tokenbuf_init(&output);
-    rc = input(src_ptr, src_ptr + src_len, 
-               &var->syntax, var->syntax_nameclass,
-               var->cb_value_fct, var->cb_value_ctx, 
-               ctx.force_expand, &output, 0, 0, NULL);
+    rc = parse_input(var, &ctx, 
+                     src_ptr, src_ptr + src_len, 
+                     ctx.force_expand, &output, 0, 0, NULL);
 
     /* post-process output */
     if (rc >= 0) {