From: Eric S. Raymond <esr@thyrsus.com>
Date: Thu, 3 Nov 1994 14:15:28 +0000 (+0000)
Subject: More comments, split out execute().
X-Git-Tag: 1-2~93
X-Git-Url: http://thyrsus.com/gitweb/?a=commitdiff_plain;h=01585de7a8ac9eb6d84417fa7c232a65bdff9e97;p=cupl.git

More comments, split out execute().
---

diff --git a/Makefile b/Makefile
index c13bd38..d8b9254 100644
--- a/Makefile
+++ b/Makefile
@@ -1,15 +1,15 @@
 #
 # Makefile for the CUPL project
 #
-CUPLDIR = .	# Not presently used -- will be if we implement the compiler
+CDEBUG = -g
 
 YFLAGS = -vlt
-CFLAGS = -g -D_POSIX_SOURCE -DYYDEBUG=1 -DPARSEDEBUG
+CFLAGS = $(CDEBUG) -D_POSIX_SOURCE -DYYDEBUG=1 -DPARSEDEBUG
 
-SOURCES = cupl.[ylh] tokdump.c main.c interpret.c
+SOURCES = cupl.[ylh] tokdump.c main.c interpret.c execute.c
 
-cupl: main.o grammar.o lexer.o interpret.o tokdump.o
-	$(CC) main.o grammar.o lexer.o interpret.o tokdump.o -o cupl
+cupl: main.o grammar.o lexer.o interpret.o tokdump.o execute.o
+	$(CC) main.o grammar.o lexer.o interpret.o tokdump.o execute.o -o cupl
 
 lexer.c: cupl.l
 	lex $(LFLAGS) cupl.l
@@ -25,6 +25,8 @@ grammar.o: grammar.c cupl.h
 tokdump.o: tokdump.c toktab.h
 lexer.o: lexer.c tokens.h cupl.h
 interpret.o: interpret.c tokens.h cupl.h
+interpret.o: interpret.c tokens.h cupl.h
+execute.o: execute.c tokens.h cupl.h
 
 toktab.h: tokens.h
 	awk <tokens.h >toktab.h '/^#/ {print $$3 ", \"" $$3 "\","}'
diff --git a/READ.ME b/READ.ME
index 584a0f1..7d2f09b 100644
--- a/READ.ME
+++ b/READ.ME
@@ -37,6 +37,7 @@ cupl.l			-- the LEX lexical-analyzer description
 cupl.h			-- fundamental types and defines 
 tokdump.c		-- token-dumper code (used for debugging)
 interpret.c		-- parse tree interpretation
+execute.c		-- actual execution
 main.c			-- cupl's main sequence
 
 			CUPL samples
diff --git a/cupl.h b/cupl.h
index f80b08d..ae39c01 100644
--- a/cupl.h
+++ b/cupl.h
@@ -54,11 +54,22 @@ typedef struct edon
 }
 node;
 
+/* this structure represents a CUPL value */
+typedef struct
+{
+    int		type;			/* type (syntax class) */
+    int		rank;			/* 0, 1, or 2 */
+    int		width, depth;		/* dimensions */
+    scalar	*elements;		/* elements */
+}
+value;
+
 /* access to the symbol list */
 typedef struct lvar_t
 {
-    struct lvar_t	*next;
-    node		*node;
+    struct lvar_t	*next;		/* link to next variable */
+    node		*node;		/* variable's symbol info */
+    value		value;		/* variable's value */
 
     /* information used for consistency checks */
     int		labeldef;
@@ -69,11 +80,14 @@ typedef struct lvar_t
 lvar;
 extern lvar *idlist;
 
+#define for_symbols(s)    for (s = idlist; s; s = s->next)
+
 #define NOMEM	"out of memory\n"
 
 extern char *tokdump(int value);
 extern void yyerror(const char *errmsg);
 extern void interpret(node *tree);
+extern void execute(node *tree);
 extern int verbose;
 
 #define DEBUG_PARSEDUMP	1
diff --git a/interpret.c b/interpret.c
index 56bc18b..362f55b 100644
--- a/interpret.c
+++ b/interpret.c
@@ -1,3 +1,17 @@
+/*****************************************************************************
+
+NAME
+   interpret.c -- parse-tree interpretation
+
+SYNOPSIS
+   void interpret(node *tree)	-- prepare and execute a parse tree
+
+DESCRIPTION
+   This code does interpretation, static checking, and label resolution
+of a CUPL parse tree.  Actual execution is handed off to execute(). 
+
+*****************************************************************************/
+/*LINTLIBRARY*/
 #include <stdio.h>
 #include <stdarg.h>
 #include "cupl.h"
@@ -24,25 +38,6 @@
 /* does the (non-VARSET) node refer to its right operand? */
 #define RIGHTREF(n)	((n) != PERFORM)
 
-/* this structure represents a CUPL value */
-typedef struct
-{
-    int		type;			/* type (syntax class) */
-    int		rank;			/* 0, 1, or 2 */
-    union
-    {
-	scalar	scalar;
-
-	struct 
-	{
-	    int		width, depth;
-	    scalar	*elements;
-	}
-	array;		/* a vector or matrix */
-    } u;
-}
-value;
-
 #ifdef PARSEDEBUG
 /*
  * Note: This prettyprint routine tries to keep cons lists of elements of the
@@ -160,7 +155,7 @@ static bool r_mark_labels(node *tp)
     return(TRUE);
 }
 
-bool recursive_apply(node *tree, bool (*fun)(node *))
+static bool recursive_apply(node *tree, bool (*fun)(node *))
 /* apply fun recursively to tree, short-circuiting on FALSE return */
 {
     if (tree == (node *)NULL)
@@ -181,8 +176,6 @@ static bool check_errors(node *tree)
     node	*n;
     lvar	*lp;
 
-#define for_symbols(s)    for (s = idlist; s; s = s->next)
-
     /* simple sanity check */
     for (n = tree; n; n = n->u.n.right)
 	if (n->type != STATEMENT)
@@ -249,7 +242,7 @@ void interpret(node *tree)
     if (check_errors(tree))
 	return;
 
-    /* actual interpretation or compilation goes here */
+    execute(tree);
 }
 
 /* interpret.c ends here */
diff --git a/tokdump.c b/tokdump.c
index 07324ab..9497adc 100644
--- a/tokdump.c
+++ b/tokdump.c
@@ -1,4 +1,17 @@
-/* tokdump.c -- a token dumper for debugging */
+/*****************************************************************************
+
+NAME
+   tokdump.c -- a token dumper for debugging
+
+
+SYNOPSIS
+   char *tokdump(int value)	-- return token name corresponding to value
+
+DESCRIPTION
+   Used for dumping the parse tree and error messages.
+
+*****************************************************************************/
+/*LINTLIBRARY*/
 
 #include <string.h>
 #include "tokens.h"