bool

commit b30dc248b357b4afd8055d55e704bf2447140d15
Author: thing1 <l.standen@posteo.com>
Date:   Tue, 14 Oct 2025 23:31:14 +0100

init commit

Diffstat:
A
.gitignore
 | 
4
++++
A
Makefile
 | 
17
+++++++++++++++++
A
bool.l
 | 
10
++++++++++
A
bool.y
 | 
57
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
expr.c
 | 
62
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
expr.h
 | 
4
++++
A
test.bool
 | 
1
+

7 files changed, 155 insertions(+), 0 deletions(-)
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1,4 @@
+lex.yy.* 
+y.* 
+bool
+	
diff --git a/Makefile b/Makefile
@@ -0,0 +1,17 @@
+CFLAGS=-ggdb
+LIBS=-lfl
+
+all: expr 
+
+lexer: bool.l
+	lex bool.l
+
+parser: bool.y
+	yacc -d bool.y
+
+expr: parser lexer expr.c
+	cc expr.c lex.yy.c y.tab.c -o bool ${LIBS} ${CFLAGS}
+
+clean:
+	rm -rf lex.yy.* y.* bool
+	
diff --git a/bool.l b/bool.l
@@ -0,0 +1,10 @@
+%{
+#include "y.tab.h"
+%}
+%%
+
+\t|\n	{;}
+[A-Z] 	{ yylval.sym = yytext[0]; return SYMBOL; }
+.	{ return yytext[0]; }
+
+%%
diff --git a/bool.y b/bool.y
@@ -0,0 +1,57 @@
+%{
+#include <stdio.h>
+#include <stdlib.h>
+#include "expr.h"
+
+extern int yylex();
+int yyerror(const char *);
+btree *program;
+char vars[26] = {0};
+
+btree *
+mkbtree(char op, btree *left, btree *right) {
+	btree *bin = malloc(sizeof(btree));
+	bin->op = op;
+	bin->left = left;
+	bin->right = right;
+	return bin;
+}
+
+%}
+
+%union {
+	struct btree *tree;
+	char sym;
+}
+
+%token <sym> SYMBOL
+
+%type <tree> expr
+%type <tree> symbol 
+
+%left '+' 
+%left '.' 
+%left '!'
+%left '(' ')'
+
+%%
+
+prog	: expr			{program = $1;}
+
+expr	: expr '.' expr		{$$ = mkbtree('.', $1, $3);}
+     	| expr '+' expr		{$$ = mkbtree('+', $1, $3);}
+	| '!' expr		{$$ = mkbtree('!', $2, NULL);}
+	| '(' expr ')'		{$$ = $2;}
+	| symbol		
+	;
+
+symbol  : SYMBOL		{$$ = mkbtree($1, NULL, NULL); vars[$1 - 65] = $1;}
+	;
+
+%%
+
+int
+yyerror(const char *s) {
+	fprintf(stderr, "error: %s\n", s);
+	return 1;
+}
diff --git a/expr.c b/expr.c
@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include "expr.h"
+
+extern FILE *yyin;
+extern void yyparse();
+extern btree *program;
+extern char vars[26];
+bool vals[26];
+
+void
+flush() {
+	while (getchar() != '\n') ;
+}
+
+bool
+eval(btree *p) {
+	bool l, r;
+	switch (p->op) {
+	case '.': 
+		l = eval(p->left);
+		r = eval(p->right);
+		return l && r;	
+	case '+': 
+		l = eval(p->left);
+		r = eval(p->right);
+		return l || r;	
+	case '!': 
+		l = eval(p->left);
+		return !l;	
+	default:
+		return vals[p->op - 65];
+	}
+}
+
+int 
+main(int argc, char **argv) {
+	yyin = stdin;
+	if (argc > 1)
+		yyin = fopen(argv[1], "r");
+	if (!yyin) {
+		fprintf(stderr, "failed to open file, using stdin\n");
+		yyin = stdin;
+	}
+
+	yyparse();
+
+	for (int i = 0; i < 26; i++) {
+		if (vars[i]) {
+			printf("%c = ", vars[i]);
+			scanf("%d", &vals[i]);
+			flush();
+		}
+	}
+
+	bool res = eval(program);
+	
+	printf("res = %s\n", (res) ? "true" : "false");
+	
+	fclose(yyin);
+	return 0;
+}
diff --git a/expr.h b/expr.h
@@ -0,0 +1,4 @@
+typedef struct btree {
+	char op;
+	struct btree *left, *right;
+} btree;
diff --git a/test.bool b/test.bool
@@ -0,0 +1 @@
+!(A.B+C)