First sanity checks are now working.

diff --git a/cupl.h b/cupl.h
index 447e0cbed985f166df0b3e79c71a5b01cb322530..84a7dd6311ce0dc5365a3f9fc53330006433b890 100644 (file)
--- a/cupl.h
+++ b/cupl.h
@@ -7,11 +7,6 @@
 #define PATH_MAX       1024
 #endif
 
-#define MAXPERFORM     64      /* depth of perform stack */
-#define MAXVARS                1024    /* maximum variables */
-#define MAXNAME                10      /* maximum length of variable names */
-#define MAXSTR         256     /* maximum string size */
-
 #ifndef CUPLDIR
 #define CUPLDIR        "/usr/lib/cupl/"
 #endif /* CUPLDIR */
@@ -37,7 +32,10 @@ typedef double scalar;
  */
 typedef struct edon
 {
-    int                type;   /* type of NODE if *left || *right */
+    /* type of the node -- a YACC token type */
+    int                type;
+
+    /* value elements of the node */
     union
     {
        struct                  /* for parse-tree nodes */
@@ -48,14 +46,11 @@ typedef struct edon
 
        scalar  numval;         /* for numbers */
 
-       char    *string;        /* for string literals */
-
-       struct                  /* for label values */
-       {
-           struct edon *dest;
-           char        *string;
-       } l;
+       char    *string;        /* for strings and identifiers */
     } u;
+
+    /* back-pointer to the symbol list, set if the node is an identifier */
+    struct lvar_t      *syminf;    
 }
 node;
 
@@ -69,7 +64,7 @@ typedef struct lvar_t
     node               *node;
 }
 lvar;
-static lvar *idlist;
+extern lvar *idlist;
 
 #define NOMEM  "out of memory\n"
 
@@ -78,4 +73,8 @@ extern void yyerror(const char *errmsg);
 extern void interpret(node *tree);
 extern int verbose;
 
+#define DEBUG_PARSEDUMP        1
+#define DEBUG_CHECKDUMP        2
+#define DEBUG_ALLOCATE 3
+
 /* cupl.h ends here */

diff --git a/cupl.l b/cupl.l
index 51068f58737331b3b28221f2e6f62bde6de78d2a..fb106451c812d425bcf91f9e593796d9fa56c3f1 100644 (file)
--- a/cupl.l
+++ b/cupl.l
@@ -11,6 +11,8 @@
 
 extern char *strdup(const char *s);
 
+lvar *idlist;
+
 static node *intern_number(char *);
 static node *intern_identifier(char *);
 static node *intern_string(char *);
@@ -118,7 +120,7 @@ static node *intern_identifier(char *str)
     }
 
 #ifdef PARSEDEBUG
-       if (verbose >= 2)
+       if (verbose >= DEBUG_ALLOCATE)
            (void) printf("intern: %9x                        (IDENTIFIER: %s)\n",
                  new, str);
 #endif /* PARSEDEBUG */
@@ -142,7 +144,7 @@ static node *intern_number(char *str)
     new->u.numval = numval;
 
 #ifdef PARSEDEBUG
-    if (verbose >= 2)
+    if (verbose >= DEBUG_ALLOCATE)
        (void) printf("intern: %9x                        (NUMBER: %f)\n", new, numval);
 #endif /* PARSEDEBUG */
     return(new);
@@ -165,7 +167,7 @@ static node *intern_string(char *str)
     new->u.string = strdup(str + 1);
 
 #ifdef PARSEDEBUG
-    if (verbose >= 2)
+    if (verbose >= DEBUG_ALLOCATE)
        (void) printf("intern: %9x                        (STRING: '%s')\n",
                      new, new->u.string);
 #endif /* PARSEDEBUG */

diff --git a/cupl.y b/cupl.y
index 08d7697df60641fbb5a061cf09ac20e84436ff2a..742086e60617f687a3c5084c2959c7b62c8550a0 100644 (file)
--- a/cupl.y
+++ b/cupl.y
@@ -272,7 +272,7 @@ node        *left, *right;  /* child nodes */
     new->u.n.right = right;
 
 #ifdef PARSEDEBUG
-    if (verbose >= 2)
+    if (verbose >= DEBUG_ALLOCATE)
        (void) printf("cons:   %9x -> %9x %9x (%s)\n",
                      new, left, right, tokdump(op));
 #endif /* PARSEDEBUG */

diff --git a/interpret.c b/interpret.c
index ee81c7b3b4933fce2caf90d48f5916e03dc2d1fa..98f58c2784af6bf542921521991fbcaf32bbb440 100644 (file)
--- a/interpret.c
+++ b/interpret.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdarg.h>
 #include "cupl.h"
 #include "tokens.h"
 
@@ -21,14 +22,6 @@ typedef struct
 }
 value;
 
-/* this structure represents a CUPL variable */
-typedef struct rav
-{
-    char       name[MAXNAME + 1];      /* name of variable */
-    value      value;
-}
-variable;
-
 #ifdef PARSEDEBUG
 /*
  * Note: This prettyprint routine tries to keep cons lists of elements of the
@@ -57,7 +50,7 @@ static void prettyprint(node *tree, int indent)
     else
     {
        (void) printf("%-20s", tokdump(tree->type));
-       if (verbose >= 2)
+       if (verbose >= DEBUG_ALLOCATE)
            (void) printf("                          (%x -> %x, %x)",
                          tree,
                          tree->u.n.left,
@@ -71,13 +64,65 @@ static void prettyprint(node *tree, int indent)
 }
 #endif /* PARSEDEBUG */
 
+static void die(char *msg, ...)
+/* complain of a fatal error and die */
+{
+    va_list    args;
+
+    va_start(args, msg);
+    vfprintf(stderr, msg, args);
+    va_end(args);
+
+    exit(1);
+}
+
+static bool check_errors(node *tree)
+/* look for inconsistencies in a program parse tree */
+{
+    node       *n;
+    lvar       *lp;
+    int                nlabels = 0;
+
+    /* make backpointers */
+    for (lp = idlist; lp; lp = lp->next)
+       lp->node->syminf = lp;
+
+    /* mark labels */
+    for (n = tree; n; n = n->u.n.right)
+       if (n->type != STATEMENT)
+           die("internal error: non-STATEMENT at top level");
+       else if (n->u.n.left->type == LABEL)
+       {
+           n->u.n.left->u.n.left->syminf->islabel = TRUE;
+           nlabels++;
+       }
+
+    /* report on the number of labels */
+    if (verbose >= DEBUG_CHECKDUMP)
+       if (nlabels == 0)
+           (void) printf("No labels.\n");
+       else
+       {
+           (void) printf("Labels:");
+           for (lp = idlist; lp; lp = lp->next)
+               if (lp->islabel)
+                   (void) printf(" %s", lp->node->u.string);
+           (void) printf("\n");
+       }
+}
+
 void interpret(node *tree)
 /* interpret a program parse tree */
 {
 #ifdef PARSEDEBUG
-    if (verbose > 0)
+    if (verbose > DEBUG_PARSEDUMP)
        prettyprint(tree, 0);
 #endif /* PARSEDEBUG */
+
+    if (check_errors(tree))
+       return;
+
+    /* actual interpretation or compilation goes here */
 }
 
 /* interpret.c ends here */

diff --git a/main.c b/main.c
index 403d0eb8c41dbcd8525c7da089ce32d1a9608891..d7a634975188eb51bf5e31c462342e52ac036f7c 100644 (file)
--- a/main.c
+++ b/main.c
@@ -77,6 +77,7 @@ char  *argv[];
        for (; optind < argc; optind++)
            if (execfile(argv[optind]))
                break;
+    return(0);
 }
 
 /* main.c ends here */