From: Mart Lubbers <mart@martlubbers.net>
Date: Wed, 16 May 2018 11:50:03 +0000 (+0200)
Subject: Fix reduction, add declarations
X-Git-Url: https://git.martlubbers.net/?a=commitdiff_plain;h=1d3d594cf37c3e15e7d2180b05041d51c32937c3;p=lambda.git

Fix reduction, add declarations
---

diff --git a/lambda.h b/lambda.h
index 2495f9d..a92a2bb 100644
--- a/lambda.h
+++ b/lambda.h
@@ -21,6 +21,12 @@ struct lambda {
 	} data;
 };
 
+struct decllist {
+	struct decllist *next;
+	char *ident;
+	struct lambda *value;
+};
+
 struct lambda *make_ident(char *);
 struct lambda *make_abstraction(char *, struct lambda *);
 struct lambda *make_application(struct lambda *, struct lambda *);
diff --git a/lambda.l b/lambda.l
index b37d888..9fe4ef4 100644
--- a/lambda.l
+++ b/lambda.l
@@ -10,15 +10,13 @@
 %%
 
 [ \t\n]
+=         return ASSIGN;
+;         return SEMICOLON;
 (\\|λ)    return LAMBDA;
 \.        return DOT;
 \(        return OBRACE;
 \)        return CBRACE;
-I         return I;
-K         return K;
-S         return S;
-F         return F;
-T         return T;
-[a-zA-Z]+ yylval = make_ident(strdup(yytext)); return IDENT;
+[a-z]+    yylval = make_ident(strdup(yytext)); return IDENT;
+[A-Z]+    yylval = make_ident(strdup(yytext)); return FUNC;
 
 %%
diff --git a/lambda.y b/lambda.y
index 4d47f9b..e65a644 100644
--- a/lambda.y
+++ b/lambda.y
@@ -4,6 +4,7 @@
 #include "mem.h"
 
 struct lambda *result;
+struct decllist *decls = NULL;
 extern int yylex();
 
 int yydebug=1;
@@ -48,24 +49,54 @@ struct lambda *make_application(struct lambda *t1, struct lambda *t2)
 	return r;
 }
 
+void decls_prepend(char *ident, struct lambda *value)
+{
+	printf("add: %s\n", ident);
+	struct decllist *head = malloc(sizeof (struct decllist));
+	head->next = decls;
+	head->ident = ident;
+	head->value = value;
+	decls = head;
+}
+
+struct lambda *decls_lookup(char *ident)
+{
+	printf("lookup: %s\n", ident);
+	struct decllist *c = decls;
+	while(c != NULL){
+		if(strcmp(c->ident, ident) == 0)
+			return copy(c->value);
+		c = c->next;
+	}
+	printf("Notfound\n");
+	return make_ident(ident);
+}
+
 %}
 
-%token LAMBDA DOT OBRACE CBRACE IDENT I K S T F
+%token LAMBDA DOT OBRACE CBRACE IDENT FUNC SEMICOLON ASSIGN
 
 %%
 
 lambda
-	: term
+	: decl lambda
+	| term
 		{ result = $$; }
+decl
+	: FUNC ASSIGN term SEMICOLON
+		{ decls_prepend($1->data.identifier, $3); }
 term
 	: term appterm
-		{
-			$$ = make_application($1, $2);
-		}
+		{ $$ = make_application($1, $2); }
 	| appterm
 		{ $$ = $1; }
 appterm
-	: IDENT
+	: FUNC
+		{
+			$$ = decls_lookup($1->data.identifier);
+			lambda_free($1);
+		}
+	| IDENT
 		{
 			$$ = make_ident($1->data.identifier);
 			lambda_free($1);
@@ -77,16 +108,3 @@ appterm
 		}
 	| OBRACE term CBRACE
 		{ $$ = $2; }
-	| I
-		{ $$ = make_abstraction("x", make_ident("x")); }
-	| K
-		{ $$ = make_abstraction("x", make_abstraction("y", make_ident("x"))); }
-	| S
-		{ $$ = make_abstraction("x", make_abstraction("y", make_abstraction("z",
-			make_application(make_application(make_ident("x"), make_ident("y")),
-				make_application(make_ident("y"), make_ident("z"))))));
-		}
-	| T
-		{ $$ = make_abstraction("x", make_abstraction("y", make_ident("x"))); }
-	| F
-		{ $$ = make_abstraction("x", make_abstraction("y", make_ident("y"))); }
diff --git a/lambda.yy.h b/lambda.yy.h
index 63c1936..f0efc72 100644
--- a/lambda.yy.h
+++ b/lambda.yy.h
@@ -466,7 +466,7 @@ extern int yylex (void);
 #undef yyTABLES_NAME
 #endif
 
-#line 24 "lambda.l"
+#line 22 "lambda.l"
 
 
 #line 473 "lambda.yy.h"
diff --git a/main.c b/main.c
index 1899d67..1c0be0f 100644
--- a/main.c
+++ b/main.c
@@ -9,7 +9,7 @@
 
 extern struct lambda *result;
 
-int main(int argc, char **argv)
+int main()
 {
 	int r = yyparse();
 	int maxdepth = 1000;
diff --git a/mem.c b/mem.c
index 19c5c8e..1e112a8 100644
--- a/mem.c
+++ b/mem.c
@@ -20,3 +20,24 @@ void lambda_free(struct lambda *t)
 	}
 	free(t);
 }
+
+struct lambda *copy(struct lambda *t)
+{
+	struct lambda *c = malloc(sizeof (struct lambda));
+	c->which = t->which;
+	switch(t->which){
+	case lambda_ident:
+		c->data.identifier = strdup(t->data.identifier);
+		break;
+	case lambda_abs:
+		c->data.abstraction.ident = strdup(t->data.abstraction.ident);
+		c->data.abstraction.expr = copy(t->data.abstraction.expr);
+		break;
+	case lambda_app:
+		c->data.application.expr1 = copy(t->data.application.expr1);
+		c->data.application.expr2 = copy(t->data.application.expr2);
+		break;
+	}
+	return c;
+}
+
diff --git a/mem.h b/mem.h
index 0cbce0d..1964654 100644
--- a/mem.h
+++ b/mem.h
@@ -4,4 +4,5 @@
 #include "lambda.h"
 
 void lambda_free(struct lambda *);
+struct lambda *copy(struct lambda *);
 #endif
diff --git a/reduce.c b/reduce.c
index 79cde99..8537a20 100644
--- a/reduce.c
+++ b/reduce.c
@@ -5,26 +5,6 @@
 #include "print.h"
 #include "mem.h"
 
-struct lambda *copy(struct lambda *t)
-{
-	struct lambda *c = malloc(sizeof (struct lambda));
-	c->which = t->which;
-	switch(t->which){
-	case lambda_ident:
-		c->data.identifier = strdup(t->data.identifier);
-		break;
-	case lambda_abs:
-		c->data.abstraction.ident = strdup(t->data.abstraction.ident);
-		c->data.abstraction.expr = copy(t->data.abstraction.expr);
-		break;
-	case lambda_app:
-		c->data.application.expr1 = copy(t->data.application.expr1);
-		c->data.application.expr2 = copy(t->data.application.expr2);
-		break;
-	}
-	return c;
-}
-
 void subst(char *ident, struct lambda *t1, struct lambda *t2, struct lambda *total)
 {
 	struct lambda cpy;
@@ -72,6 +52,7 @@ void lambda_reduce(struct lambda *t, struct lambda *total, int *maxdepth)
 			(*maxdepth)--;
 			if(total == t)
 				*total = *t1->data.abstraction.expr;
+			*t = *t1->data.abstraction.expr;
 			printf("-> ");
 			lambda_print(total);
 			lambda_reduce(t, total, maxdepth);