1 files changed, 605 insertions, 0 deletions

diff --git a/src/parser.c b/src/parser.c
new file mode 100644
index 0000000..e8c44df
--- /dev/null
+++ b/src/parser.c
@@ -0,0 +1,605 @@
+#include "parser.h"
+#include "ast.h"
+#include "token.h"
+#include "vector.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+enum precedence {
+	PRE_LOWEST = 1,
+	PRE_EQUALS,
+	PRE_LG,
+	PRE_SUM,
+	PRE_PROD,
+	PRE_PREFIX,
+	PRE_CALL,
+};
+
+static enum precedence precedences[] = {
+	0,
+	PRE_LOWEST,
+	PRE_EQUALS,
+	PRE_LG,
+	PRE_SUM,
+	PRE_PROD,
+	PRE_PREFIX,
+	PRE_CALL,
+};
+
+static inline void
+parser_register_prefix(struct parser *parser, enum token_type t,
+		prefix_parse_f fn)
+{
+	hmap_set(parser->prefix_fns, token_type_print(t), fn);
+}
+
+static inline void
+parser_register_infix(struct parser *parser, enum token_type t,
+		infix_parse_f fn)
+{
+	hmap_set(parser->infix_fns, token_type_print(t), fn);
+}
+
+static inline void
+parser_register_precedence(struct parser *parser, enum token_type t,
+		enum precedence pre)
+{
+	hmap_set(parser->precedences, token_type_print(t), &precedences[pre]);
+}
+
+static inline prefix_parse_f
+parser_get_prefix(struct parser *parser, enum token_type t)
+{
+	return hmap_get(parser->prefix_fns, token_type_print(t));
+}
+
+static inline infix_parse_f
+parser_get_infix(struct parser *parser, enum token_type t)
+{
+	return hmap_get(parser->infix_fns, token_type_print(t));
+}
+
+static inline enum precedence
+parser_get_precedence(struct parser *parser, enum token_type t)
+{
+	enum precedence *pre = hmap_get(parser->precedences, token_type_print(t));
+	if (!pre) return PRE_LOWEST;
+	return *pre;
+}
+
+static inline bool
+parser_cur_token_is(struct parser *parser, enum token_type t)
+{
+	return parser->cur_token.type == t;
+}
+
+static inline bool
+parser_peek_token_is(struct parser *parser, enum token_type t)
+{
+	return parser->peek_token.type == t;
+}
+
+static inline enum precedence
+parser_peek_precedence(struct parser *parser)
+{
+	return parser_get_precedence(parser, parser->peek_token.type);
+}
+
+static inline enum precedence
+parser_cur_precedence(struct parser *parser)
+{
+	return parser_get_precedence(parser, parser->cur_token.type);
+}
+
+static inline void
+parser_peek_error(struct parser *parser, enum token_type t)
+{
+	char *msg = malloc(sizeof(*msg) * 1024);
+	if (msg) {
+		sprintf(msg, "expected token %s, got %s", token_type_print(t),
+				token_type_print(parser->peek_token.type));
+		vector_push(parser->errors, msg);
+	}
+}
+
+static inline bool
+parser_expect_peek(struct parser *parser, enum token_type t)
+{
+	if (parser_peek_token_is(parser, t)) {
+		parser_next_token(parser);
+		return true;
+	}
+	parser_peek_error(parser, t);
+	return false;
+}
+
+static inline void
+parser_no_prefix_fn_error(struct parser *parser, enum token_type t)
+{
+	char *msg = malloc(256);
+	sprintf(msg, "%s not recognized as prefix", token_type_print(t));
+	vector_push(parser->errors, msg);
+}
+
+static struct expression *
+parser_parse_expression(struct parser *parser, enum precedence pre)
+{
+	prefix_parse_f prefix = parser_get_prefix(parser, parser->cur_token.type);
+	if (!prefix) {
+		parser_no_prefix_fn_error(parser, parser->cur_token.type);
+		return NULL;
+	}
+	struct expression *lexpr = prefix(parser);
+
+	while (pre < parser_peek_precedence(parser)
+			&& !parser_peek_token_is(parser, TOKEN_SEMICOLON)) {
+		infix_parse_f infix = parser_get_infix(parser, parser->peek_token.type);
+		if (!infix) {
+			return lexpr;
+		}
+
+		parser_next_token(parser);
+		lexpr = infix(parser, lexpr);
+	}
+
+	return lexpr;
+}
+
+static struct expression *
+parser_parse_identifier(struct parser *parser)
+{
+	struct expression *expr = malloc(sizeof(*expr));
+	expr->type = EXPRESSION_IDENT;
+	expr->token = parser->cur_token;
+	expr->ident.value = parser->cur_token.literal;
+
+	return expr;
+}
+
+static struct expression *
+parser_parse_integer(struct parser *parser)
+{
+	struct expression *expr = malloc(sizeof(*expr));
+	expr->type = EXPRESSION_INT;
+	expr->token = parser->cur_token;
+
+	char *end;
+	expr->integer.value = strtol(expr->token.literal.str 
+			+ expr->token.literal.start,
+			&end, 0);
+	if (*end != '\0' && (expr->token.literal.str + expr->token.literal.end) < end) {
+		char *msg = malloc(256);
+		char litbuf[32];
+		sprintf(msg, "%s is not a valid integer",
+				slice_sprint(&expr->token.literal, litbuf));
+		vector_push(parser->errors, msg);
+		free(expr);
+		return NULL;
+	}
+
+	return expr;
+}
+
+static struct expression *
+parser_parse_boolean(struct parser *parser)
+{
+	struct expression *expr = malloc(sizeof(*expr));
+	expr->type = EXPRESSION_BOOL;
+	expr->token = parser->cur_token;
+	expr->boolean.value = expr->token.type == TOKEN_TRUE;
+
+	return expr;
+}
+
+static struct expression *
+parser_parse_grouped(struct parser *parser)
+{
+	parser_next_token(parser);
+	struct expression *expr = parser_parse_expression(parser, PRE_LOWEST);
+	if (!parser_expect_peek(parser, TOKEN_RPAREN)) {
+		return NULL;
+	}
+
+	return expr;
+}
+
+static struct expression *
+parser_parse_prefix(struct parser *parser)
+{
+	struct expression *expr = malloc(sizeof(*expr));
+	expr->type = EXPRESSION_PREFIX;
+	expr->token = parser->cur_token;
+	expr->prefix.operator = parser->cur_token.literal;
+
+	parser_next_token(parser);
+	expr->prefix.right = parser_parse_expression(parser, PRE_PREFIX);
+
+	return expr;
+}
+
+static struct expression *
+parser_parse_infix(struct parser *parser, struct expression *lexpr)
+{
+	struct expression *expr = malloc(sizeof(*expr));
+	expr->type = EXPRESSION_INFIX;
+	expr->token = parser->cur_token;
+	expr->infix.operator = parser->cur_token.literal;
+	expr->infix.left = lexpr;
+
+	enum precedence pre = parser_cur_precedence(parser);
+	parser_next_token(parser);
+	expr->infix.right = parser_parse_expression(parser, pre);
+
+	return expr;
+}
+
+static struct statement *
+parser_parse_let_statement(struct parser *parser)
+{
+	struct statement *st = calloc(1, sizeof(*st));
+	if (!st) return NULL;
+	st->type = STATEMENT_LET;
+	st->token = parser->cur_token;
+
+	if (!parser_expect_peek(parser, TOKEN_IDENT)) goto fail;
+
+	st->let.name = malloc(sizeof(*st->let.name));
+	if (!st->let.name) goto fail;
+	st->let.name->token = parser->cur_token;
+	st->let.name->value = parser->cur_token.literal;
+
+	if (!parser_expect_peek(parser, TOKEN_ASSIGN)) goto ass_fail;
+
+	parser_next_token(parser);
+
+	st->let.value = parser_parse_expression(parser, PRE_LOWEST);
+	if (parser_peek_token_is(parser, TOKEN_SEMICOLON)) {
+		parser_next_token(parser);
+	}
+
+	return st;
+ass_fail:
+	free(st->let.name);
+fail:
+	free(st);
+	return NULL;
+}
+
+static struct statement *
+parser_parse_return_statement(struct parser *parser)
+{
+	struct statement *st = calloc(1, sizeof(*st));
+	if (!st) return NULL;
+	st->type = STATEMENT_RETURN;
+	st->token = parser->cur_token;
+
+	parser_next_token(parser);
+
+	st->retrn.value = parser_parse_expression(parser, PRE_LOWEST);
+	if (parser_peek_token_is(parser, TOKEN_SEMICOLON)) {
+		parser_next_token(parser);
+	}
+
+	return st;
+}
+
+static struct statement *
+parser_parse_expression_statement(struct parser *parser)
+{
+	struct statement *st = calloc(1, sizeof(*st));
+	if (!st) return NULL;
+	st->type = STATEMENT_EXPRESSION;
+	st->token = parser->cur_token;
+	st->expr.expr = parser_parse_expression(parser, PRE_LOWEST);
+
+	if (parser_peek_token_is(parser, TOKEN_SEMICOLON)) {
+		parser_next_token(parser);
+	}
+
+	return st;
+}
+
+static struct statement *parser_parse_statement(struct parser *);
+
+static struct statement *
+parser_parse_block_statement(struct parser *parser)
+{
+	struct statement *st = calloc(1, sizeof(*st));
+	if (!st) return NULL;
+	st->type = STATEMENT_BLOCK;
+	st->block.statements = vector_new();
+	parser_next_token(parser);
+
+	while (!parser_cur_token_is(parser, TOKEN_RBRACE) 
+			&& !parser_cur_token_is(parser, TOKEN_EOF)) {
+		struct statement *subst = parser_parse_statement(parser);
+		if (subst) {
+			vector_push(st->block.statements, subst);
+		}
+		parser_next_token(parser);
+	}
+
+	return st;
+}
+
+static struct expression *
+parser_parse_if(struct parser *parser)
+{
+	struct expression *expr = calloc(1, sizeof(*expr));
+	expr->type = EXPRESSION_IF;
+	expr->token = parser->cur_token;
+
+	if (!parser_expect_peek(parser, TOKEN_LPAREN)) {
+		goto fail;
+	}
+
+	parser_next_token(parser);
+	expr->cond.condition = parser_parse_expression(parser, PRE_LOWEST);
+
+	if (!parser_expect_peek(parser, TOKEN_RPAREN)) {
+		goto fail;
+	}
+	if (!parser_expect_peek(parser, TOKEN_LBRACE)) {
+		goto fail;
+	}
+
+	expr->cond.consequence = parser_parse_block_statement(parser);
+
+	if (parser_peek_token_is(parser, TOKEN_ELSE)) {
+		parser_next_token(parser);
+		if (!parser_expect_peek(parser, TOKEN_LBRACE)) {
+			goto fail;
+		}
+		expr->cond.alternative = parser_parse_block_statement(parser);
+	}
+
+	return expr;
+fail:
+	free(expr);
+	return NULL;
+}
+
+static struct vector *
+parser_parse_func_params(struct parser *parser)
+{
+	struct vector *idents = vector_new_with_cap(8);
+
+	if (parser_peek_token_is(parser, TOKEN_RPAREN)) {
+		parser_next_token(parser);
+		return idents;
+	}
+
+	parser_next_token(parser);
+
+	struct expression *ident = calloc(1, sizeof(*ident));
+	ident->token = parser->cur_token;
+	ident->ident.value = parser->cur_token.literal;
+	vector_push(idents, ident);
+	while (parser_peek_token_is(parser, TOKEN_COMMA)) {
+		parser_next_token(parser);
+		parser_next_token(parser);
+		ident = calloc(1, sizeof(*ident));
+		ident->token = parser->cur_token;
+		ident->ident.value = parser->cur_token.literal;
+		vector_push(idents, ident);
+	}
+
+	if (!parser_expect_peek(parser, TOKEN_RPAREN)) {
+		size_t i;
+		vector_foreach(idents, i, ident) {
+			expression_destroy(ident);
+		}
+		vector_free(idents);
+		return NULL;
+	}
+
+	return idents;
+}
+
+static struct expression *
+parser_parse_func_literal(struct parser *parser)
+{
+	struct expression *expr = calloc(1, sizeof(*expr));
+	expr->type = EXPRESSION_FUNC;
+	expr->token = parser->cur_token;
+
+	if (!parser_expect_peek(parser, TOKEN_LPAREN)) {
+		goto fail;
+	}
+	expr->func.parameters = parser_parse_func_params(parser);
+	if (!parser_expect_peek(parser, TOKEN_LBRACE)) {
+		goto fail;
+	}
+
+	expr->func.body = parser_parse_block_statement(parser);
+
+	return expr;
+fail:
+	free(expr);
+	return NULL;
+}
+
+static struct vector *
+parser_parse_call_arguments(struct parser *parser)
+{
+	struct vector *args = vector_new_with_cap(8);
+
+	if (parser_peek_token_is(parser, TOKEN_RPAREN)) {
+		parser_next_token(parser);
+		return args;
+	}
+
+	parser_next_token(parser);
+	vector_push(args, parser_parse_expression(parser, PRE_LOWEST));
+
+	while (parser_peek_token_is(parser, TOKEN_COMMA)) {
+		parser_next_token(parser);
+		parser_next_token(parser);
+		vector_push(args, parser_parse_expression(parser, PRE_LOWEST));
+	}
+
+	if (!parser_expect_peek(parser, TOKEN_RPAREN)) {
+		size_t i;
+		struct expression *expr;
+		vector_foreach(args, i, expr) {
+			expression_destroy(expr);
+		}
+		vector_free(args);
+		return NULL;
+	}
+
+	return args;
+}
+
+static struct expression *
+parser_parse_call_expression(struct parser *parser, struct expression *func)
+{
+	struct expression *expr = calloc(1, sizeof(*expr));
+	expr->token = parser->cur_token;
+	expr->type = EXPRESSION_CALL;
+	expr->call.func = func;
+	expr->call.arguments = parser_parse_call_arguments(parser);
+	
+	return expr;
+}
+
+static struct statement *
+parser_parse_statement(struct parser *parser)
+{
+	switch (parser->cur_token.type) {
+	case TOKEN_LET:
+		return parser_parse_let_statement(parser);
+	case TOKEN_RETURN:
+		return parser_parse_return_statement(parser);
+	case TOKEN_LBRACE:
+		return parser_parse_block_statement(parser);
+	default:
+		return parser_parse_expression_statement(parser);
+	}
+}
+
+struct parser *
+parser_new()
+{
+	struct parser *parser = malloc(sizeof *parser);
+	if (!parser) return NULL;
+
+	struct lexer *lex = lexer_new();
+	if (!lex) goto fail;
+	parser->lexer = lex;
+
+	parser->errors = vector_new();
+	if (!parser->errors) goto fail2;
+
+	parser->prefix_fns = hmap_new();
+	if (!parser->prefix_fns) goto fail3;
+	parser_register_prefix(parser, TOKEN_IDENT, parser_parse_identifier);
+	parser_register_prefix(parser, TOKEN_INT, parser_parse_integer);
+	parser_register_prefix(parser, TOKEN_BANG, parser_parse_prefix);
+	parser_register_prefix(parser, TOKEN_MINUS, parser_parse_prefix);
+	parser_register_prefix(parser, TOKEN_TRUE, parser_parse_boolean);
+	parser_register_prefix(parser, TOKEN_FALSE, parser_parse_boolean);
+	parser_register_prefix(parser, TOKEN_LPAREN, parser_parse_grouped);
+	parser_register_prefix(parser, TOKEN_RPAREN, parser_parse_grouped);
+	parser_register_prefix(parser, TOKEN_IF, parser_parse_if);
+	parser_register_prefix(parser, TOKEN_FUNC, parser_parse_func_literal);
+
+	parser->infix_fns = hmap_new();
+	if (!parser->infix_fns) goto fail4;
+	parser_register_infix(parser, TOKEN_PLUS, parser_parse_infix);
+	parser_register_infix(parser, TOKEN_MINUS, parser_parse_infix);
+	parser_register_infix(parser, TOKEN_SLASH, parser_parse_infix);
+	parser_register_infix(parser, TOKEN_ASTERISK, parser_parse_infix);
+	parser_register_infix(parser, TOKEN_EQ, parser_parse_infix);
+	parser_register_infix(parser, TOKEN_NOTEQ, parser_parse_infix);
+	parser_register_infix(parser, TOKEN_LT, parser_parse_infix);
+	parser_register_infix(parser, TOKEN_GT, parser_parse_infix);
+	parser_register_infix(parser, TOKEN_LPAREN, parser_parse_call_expression);
+	
+	parser->precedences = hmap_new();
+	if (!parser->precedences) goto fail5;
+	parser_register_precedence(parser, TOKEN_EQ, PRE_EQUALS);
+	parser_register_precedence(parser, TOKEN_NOTEQ, PRE_EQUALS);
+	parser_register_precedence(parser, TOKEN_LT, PRE_LG);
+	parser_register_precedence(parser, TOKEN_GT, PRE_LG);
+	parser_register_precedence(parser, TOKEN_PLUS, PRE_SUM);
+	parser_register_precedence(parser, TOKEN_MINUS, PRE_SUM);
+	parser_register_precedence(parser, TOKEN_ASTERISK, PRE_PROD);
+	parser_register_precedence(parser, TOKEN_SLASH, PRE_PROD);
+	parser_register_precedence(parser, TOKEN_LPAREN, PRE_CALL);
+
+	return parser;
+fail5:
+	hmap_free(parser->infix_fns);
+fail4:
+	hmap_free(parser->prefix_fns);
+fail3:
+	vector_free(parser->errors);
+fail2:
+	lexer_destroy(lex);
+fail:
+	free(parser);
+	return NULL;
+}
+
+void
+parser_reset(struct parser *parser, const char *input)
+{
+	size_t i;
+	char *val;
+	vector_foreach (parser->errors, i, val) {
+		free(val);
+	}
+	parser->errors->len = 0;
+
+	lexer_reset(parser->lexer, input);
+
+	parser_next_token(parser);
+	parser_next_token(parser);
+}
+
+void
+parser_next_token(struct parser *parser)
+{
+	parser->cur_token = parser->peek_token;
+	parser->peek_token = lexer_next_token(parser->lexer);
+}
+
+struct program *
+parser_parse_program(struct parser *parser)
+{
+	struct program *program = malloc(sizeof *program);
+	if (!program) return NULL;
+	program->statements = vector_new();
+	if (!program->statements) {
+		free(program);
+		return NULL;
+	}
+
+	while (!parser_cur_token_is(parser, TOKEN_EOF)) {
+		struct statement *st = parser_parse_statement(parser);
+		if (st != NULL) {
+			vector_push(program->statements, st);
+		}
+		parser_next_token(parser);
+	}
+
+	return program;
+}
+
+void
+parser_destroy(struct parser *parser)
+{
+	size_t i;
+	char *val;
+	vector_foreach (parser->errors, i, val) {
+		free(val);
+	}
+	vector_free(parser->errors);
+	hmap_free(parser->infix_fns);
+	hmap_free(parser->prefix_fns);
+	hmap_free(parser->precedences);
+	lexer_destroy(parser->lexer);
+	free(parser);
+}