From 4fba3e66dce0d167d2031a0d1f1f6f4571cbd981 Mon Sep 17 00:00:00 2001
From: Peter Mikkelsen <peter@pmikkelsen.com>
Date: Tue, 27 Jul 2021 15:20:29 +0000
Subject: Don't use strings to identify vars, use numbers

---
 parser.c | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

(limited to 'parser.c')

diff --git a/parser.c b/parser.c
index 51eb436..9ce68f1 100644
--- a/parser.c
+++ b/parser.c
@@ -42,6 +42,7 @@ enum {
 static Biobuf *parsein;
 static Token lookahead;
 static Module *currentmod;
+static VarName *varnames;
 
 void nexttoken(void);
 Term *fullterm(int, Rune *, Term *);
@@ -49,19 +50,22 @@ Term *term(void);
 Term *listterm(int);
 Term *curlybracketterm(void);
 Term *compound(void);
+Term *parsevar(void);
 Term *parseoperators(Term *);
 void match(int);
 void syntaxerror_parser(char *);
 Term *parseterm(void);
 
 Term *
-parse(Biobuf *bio, Module *mod)
+parse(Biobuf *bio, Module *mod, VarName **vns)
 {
 	parsein = bio;
 	currentmod = mod;
+	varnames = nil;
 	nexttoken();
 
 	Term *result = parseterm();
+	*vns = varnames;
 	if(result){
 		result = copyterm(result, &clausenr);
 		clausenr++;
@@ -107,8 +111,7 @@ term(void)
 		result = compound();
 		break;
 	case VarTok:
-		result = mkvariable(lookahead.text);
-		match(VarTok);
+		result = parsevar();
 		break;
 	case IntTok:
 		result = mkinteger(lookahead.ival);
@@ -201,6 +204,29 @@ compound(void)
 	return mkcompound(name, arity, args);
 }
 
+Term *
+parsevar(void)
+{
+	Rune *name = lookahead.text;
+	match(VarTok);
+
+	VarName *vn;
+	uvlong i = 0;
+	for(vn = varnames; vn != nil; vn = vn->next, i++)
+		if(runestrcmp(vn->name, name) == 0 && !runestrcmp(vn->name, L"_") == 0){
+			vn->count++;
+			return copyterm(vn->var, nil);
+		}
+
+	VarName *new = gmalloc(sizeof(VarName));
+	new->name = name;
+	new->var = mkvariable();
+	new->count = 1;
+	new->next = varnames;
+	varnames = new;
+	return new->var;
+}
+
 Term *
 parseoperators(Term *list)
 {
-- 
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