feat: implement lexer+parser for example program

src/compiler/fzl_parser.c

@@ -0,0 +1,214 @@
+#include <compiler/fzl_parser.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+char last_err[256];
+
+fzl_parser_t *fzl_mkparser(fzl_reader_ll_t *first)
+{
+	if (!first)
+	{
+		snprintf(last_err, sizeof(last_err), "token is null");
+		return NULL;
+	}
+
+	fzl_parser_t *parser = malloc(sizeof(fzl_parser_t));
+	if (!parser) return NULL;
+
+	parser->root = NULL;
+	parser->cursor = first->next;
+	if (!parser->cursor) return NULL;
+
+	return parser;
+}
+
+// --- Parse zone ---
+
+// Make a new node
+fzl_node_t *fzl_mknode(fzl_nodetype_t type, fzl_token_t *token)
+{
+	fzl_node_t *node = malloc(sizeof(fzl_node_t));
+
+	if (!node) return NULL;
+	node->type = type;
+	node->token = token;
+	node->parent = NULL;
+	node->next = NULL;
+
+	return node;
+}
+
+// Get token at cursor
+static fzl_token_t *peek(fzl_parser_t *parser)
+{
+	if (!parser->cursor) return NULL;
+	return parser->cursor->token;
+}
+
+// Get token at (cursor + 1)
+static fzl_token_t *next(fzl_parser_t *parser)
+{
+	if (!parser->cursor) return NULL;
+	
+	fzl_reader_ll_t *next = parser->cursor->next;
+	if (!next) return NULL;
+
+	return next->token;
+}
+
+// Consume token at cursor and move to the next
+static fzl_token_t *consume(fzl_parser_t *parser)
+{
+	if (!parser->cursor) return NULL;
+	fzl_token_t *tok = parser->cursor->token;
+	parser->cursor = parser->cursor->next;
+	return tok;
+}
+
+// Parse primary
+fzl_node_t *parse_primary(fzl_parser_t *parser)
+{
+	if (peek(parser) && peek(parser)->type == FZL_TOKTYPE_STR_LITERAL)
+	{
+		fzl_token_t *tok = consume(parser);
+		return fzl_mknode(FZL_NODETYPE_LITERAL, tok);
+	}
+
+	snprintf(last_err, sizeof(last_err),
+					 "failed to parse primary at %d", peek(parser)->i0);
+	return NULL;
+}
+
+fzl_node_t *parse_expression(fzl_parser_t *parser, int precedence);
+
+// Parse call expression
+fzl_node_t *parse_call(fzl_parser_t *parser)
+{
+	fzl_token_t *tok = consume(parser); // <NAME>
+	consume(parser); // (
+	
+	fzl_node_t *node = fzl_mknode(FZL_NODETYPE_CALL, tok);
+	node->list.entry_count = 0;
+
+	size_t capacity = 4;
+	node->list.entries = malloc(capacity * sizeof(fzl_node_t*));
+	node->list.entry_count = 0;
+
+	if (peek(parser) && peek(parser)->type == FZL_TOKTYPE_RPAIR)
+	{
+		consume(parser);
+		return node;
+	}
+
+	while (peek(parser) && peek(parser)->type != FZL_TOKTYPE_RPAIR)
+	{
+		fzl_node_t *arg = parse_expression(parser, 0);
+		if (!arg) return NULL;
+
+		if (node->list.entry_count == capacity)
+		{
+			capacity *= 2;
+			node->list.entries = realloc(node->list.entries, capacity * sizeof(fzl_node_t*));
+		}
+
+		node->list.entries[node->list.entry_count++] = arg;
+
+		if (peek(parser) && peek(parser)->type == FZL_TOKTYPE_COMMA)
+			consume(parser);
+		else if (peek(parser) && peek(parser)->type != FZL_TOKTYPE_RPAIR)
+		{
+			snprintf(last_err, sizeof(last_err), "expected ',' or ')' after arg list");
+			return NULL;
+		}
+	}
+
+	consume(parser);
+	return node;
+}
+
+// Expression parsing
+fzl_node_t *parse_expression(fzl_parser_t *parser, int precedence)
+{
+	if (peek(parser) && peek(parser)->type == FZL_TOKTYPE_NAME)
+	{
+		if (next(parser) && next(parser)->type == FZL_TOKTYPE_LPAIR)
+			return parse_call(parser);
+	}
+	else if (peek(parser) && peek(parser)->type == FZL_TOKTYPE_STR_LITERAL)
+		return parse_primary(parser);
+
+	snprintf(last_err, sizeof(last_err),
+					 "failed to parse expression at %d",
+					 peek(parser)->i0);
+	return NULL;
+}
+
+// Statement parsing
+fzl_node_t *parse_statement(fzl_parser_t *parser)
+{
+	return parse_expression(parser, 0);
+}
+
+// Internal parsing entry point
+fzl_node_t *parse_program(fzl_parser_t *parser)
+{
+	fzl_node_t *first = NULL;
+	fzl_node_t *last = NULL;
+	fzl_node_t *node = NULL;
+	while (peek(parser) != NULL)
+	{
+		node = parse_statement(parser);
+		if (!node) return NULL;
+
+		if (!last)
+		{
+			first = node;
+			last = node;
+		}
+		else
+		{
+			last->next = node;
+			last = node;
+		}
+	}
+
+	if (!first)
+	{
+		snprintf(last_err, sizeof(last_err), "empty ;(");
+		return NULL;
+	}
+
+	return first;
+}
+
+
+// Parse tokens and build AST
+int fzl_parse(fzl_parser_t *parser)
+{
+	fzl_node_t *ast = parse_program(parser);
+	if (!ast) return -1;
+
+	parser->root = ast;
+	return 0;
+}
+
+// --- Parse zone end ---
+
+char *fzl_parser_geterror()
+{
+	return last_err;
+}
+
+void fzl_freenode(fzl_node_t *node)
+{
+	if (!node) return;
+	if (node->token) fzl_freetoken(node->token);
+	free(node);
+}
+
+void fzl_freeparser(fzl_parser_t *parser)
+{
+	if (!parser) return;
+	free(parser);
+}
+