From: Eric S. Raymond <esr@thyrsus.com>
Date: Thu, 3 Nov 1994 00:01:34 +0000 (+0000)
Subject: First sanity checks are now working.
X-Git-Tag: 1-2~106
X-Git-Url: http://thyrsus.com/gitweb/?a=commitdiff_plain;h=366439c173c2e1b4a2c3f0d1157a8e67d702eb4f;p=cupl.git

First sanity checks are now working.
---

diff --git a/cupl.h b/cupl.h
index 447e0cb..84a7dd6 100644
--- 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 51068f5..fb10645 100644
--- 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 08d7697..742086e 100644
--- 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 ee81c7b..98f58c2 100644
--- 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 403d0eb..d7a6349 100644
--- 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 */