1 files changed, 111 insertions, 0 deletions
diff --git a/src/parser.y b/src/parser.y
new file mode 100644
index 0000000..878a9a5
--- /dev/null
+++ b/src/parser.y
@@ -0,0 +1,111 @@
+%{
+#include <ctype.h>
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "lexer.h"
+#include "parser.h"
+
+static ast_t astmerge(int, ast_t, ast_t);
+static void *xmalloc(size_t);
+static void yyerror(const char *);
+%}
+
+%code requires {
+#include "pinocchio.h"
+}
+
+%union {
+	char  ch;
+	ast_t ast;
+}
+
+%define parse.error verbose
+%locations
+
+/* Very important that NOT is the first token declared!  Code depends on it. */
+
+%start input
+%type  <ast> line exp
+%token <ast> NOT AND OR XOR IMPL EQUIV OPAR CPAR
+%token <ch>  IDENT
+%token EOL
+
+%left OR
+%left AND
+%left XOR
+%left IMPL EQUIV
+%nonassoc NOT
+
+%%
+
+input
+	: %empty
+	| input line { astprocess($2); }
+	;
+
+line
+	:     EOL { $$.eqn = NULL; }
+	| exp EOL { $$ = $1; }
+	;
+
+exp
+	: IDENT {
+		$$.eqn = xmalloc(sizeof(eqn_t));
+		$$.eqn->type = IDENT;
+		$$.eqn->ch  = $1;
+		$$.vars = 1 << (islower($1) ? $1-'a'+26 : $1-'A');
+	}
+	| NOT exp {
+		eqn_t *node = xmalloc(sizeof(eqn_t));
+		node->type = NOT;
+		node->rhs  = $2.eqn;
+		$$.eqn = node;
+		$$.vars = $2.vars;
+	}
+	| OPAR exp CPAR {
+		eqn_t *node = xmalloc(sizeof(eqn_t));
+		node->type = OPAR;
+		node->rhs  = $2.eqn;
+		$$.eqn = node;
+		$$.vars = $2.vars;
+	}
+	| exp AND   exp { $$ = astmerge(AND,   $1, $3); }
+	| exp OR    exp { $$ = astmerge(OR,    $1, $3); }
+	| exp XOR   exp { $$ = astmerge(XOR,   $1, $3); }
+	| exp IMPL  exp { $$ = astmerge(IMPL,  $1, $3); }
+	| exp EQUIV exp { $$ = astmerge(EQUIV, $1, $3); }
+	;
+
+%%
+
+ast_t
+astmerge(int op, ast_t lhs, ast_t rhs)
+{
+	ast_t a = {
+		.eqn  = xmalloc(sizeof(eqn_t)),
+		.vars = lhs.vars | rhs.vars,
+	};
+	a.eqn->type = op;
+	a.eqn->lhs = lhs.eqn;
+	a.eqn->rhs = rhs.eqn;
+	return a;
+}
+
+void *
+xmalloc(size_t n)
+{
+	void *p = malloc(n);
+	if (p == NULL)
+		err(1, "malloc");
+	return p;
+}
+
+void
+yyerror(const char *s)
+{
+	/* TODO: Get filename */
+	fprintf(stderr, "pinocchio: -:%d: %s\n", yylloc.first_line, s);
+	exit(EXIT_FAILURE);
+}