From 33824534bcb63147621f91803b200ae8bbf452f5 Mon Sep 17 00:00:00 2001
From: Chewing_Bever <roosensjef@gmail.com>
Date: Fri, 15 Mar 2024 22:24:19 +0100
Subject: [PATCH] fix(parser): fix blatant bug with lexer handling

---
 src/_include/mrk/parser_internal.h |  7 ++----
 src/parser/parser.c                | 12 ++++++-----
 src/parser/util.c                  | 34 +++++++++---------------------
 test/parser/compound.c             | 33 +++++++++++++++++++++++++++++
 4 files changed, 52 insertions(+), 34 deletions(-)
 create mode 100644 test/parser/compound.c

diff --git a/src/_include/mrk/parser_internal.h b/src/_include/mrk/parser_internal.h
index 8722bf5..fb22c71 100644
--- a/src/_include/mrk/parser_internal.h
+++ b/src/_include/mrk/parser_internal.h
@@ -1,7 +1,7 @@
 #ifndef MRK_PARSER_INTERNAL
 #define MRK_PARSER_INTERNAL
 
-#include "mrk/lexer_internal.h"
+#include "mrk/lexer.h"
 #include "mrk/parser.h"
 
 #define MRK_PARSER_LOOKAHEAD_BUF_SIZE 4
@@ -12,10 +12,7 @@
 
 struct mrk_parser {
   mrk_lexer *lexer;
-  struct {
-    mrk_token buf[MRK_PARSER_LOOKAHEAD_BUF_SIZE];
-    size_t index;
-  } lookahead;
+  mrk_token next_token;
   struct {
     mrk_token token;
     const char *msg;
diff --git a/src/parser/parser.c b/src/parser/parser.c
index dbfeb13..3a5a581 100644
--- a/src/parser/parser.c
+++ b/src/parser/parser.c
@@ -1,4 +1,5 @@
 #include "mrk/parser_internal.h"
+#include <stdio.h>
 
 mrk_err mrk_parser_init(mrk_parser **out) {
   MRK_CALLOC(out, 1, sizeof(mrk_parser));
@@ -9,11 +10,8 @@ mrk_err mrk_parser_init(mrk_parser **out) {
 void mrk_parser_open(mrk_parser *parser, mrk_lexer *lexer) {
   parser->lexer = lexer;
 
-  // Prefill lookahead buffer
-  for (size_t i = 0;
-       i < MRK_PARSER_LOOKAHEAD_BUF_SIZE && !mrk_lexer_done(lexer); i++) {
-    mrk_lexer_next(&parser->lookahead.buf[i], lexer);
-  }
+  // Prefill lookahead character
+  mrk_parser_advance(parser);
 }
 
 mrk_err mrk_parser_parse(mrk_ast_node **out, mrk_parser *parser) {
@@ -28,6 +26,10 @@ mrk_err mrk_parser_parse(mrk_ast_node **out, mrk_parser *parser) {
     case mrk_token_type_header_start:
       MRK_RES(mrk_parser_parse_header(child, parser));
       break;
+    case mrk_token_type_text:
+    case mrk_token_type_left_bracket:
+      MRK_RES(mrk_parser_parse_paragraph(child, parser));
+      break;
     }
   }
 
diff --git a/src/parser/util.c b/src/parser/util.c
index 0bd06db..9ec58d3 100644
--- a/src/parser/util.c
+++ b/src/parser/util.c
@@ -2,35 +2,21 @@
 
 bool mrk_parser_done(mrk_parser *parser) {
   return mrk_lexer_done(parser->lexer) &&
-         parser->lookahead.buf[parser->lookahead.index].type ==
-             mrk_token_type_none;
+         parser->next_token.type == mrk_token_type_none;
 }
 
-mrk_token mrk_parser_peek(mrk_parser *parser) {
-  mrk_token out;
-
-  if (mrk_parser_done(parser)) {
-    out.type = mrk_token_type_none;
-  } else {
-    out = parser->lookahead.buf[parser->lookahead.index];
-  }
-
-  return out;
-}
+mrk_token mrk_parser_peek(mrk_parser *parser) { return parser->next_token; }
 
 void mrk_parser_advance(mrk_parser *parser) {
-  if (mrk_parser_done(parser)) {
-    return;
+  switch (mrk_lexer_next(&parser->next_token, parser->lexer)) {
+  case mrk_lexer_err_ok:
+  // TODO handle this better
+  case mrk_lexer_err_unexpected_char:
+    break;
+  case mrk_lexer_err_done:
+    parser->next_token.type = mrk_token_type_none;
+    break;
   }
-
-  // Append new element of the lexer to the lookahead buffer
-  if (!mrk_lexer_done(parser->lexer)) {
-    mrk_lexer_next(&parser->lookahead.buf[parser->lookahead.index],
-                   parser->lexer);
-  }
-
-  parser->lookahead.index =
-      (parser->lookahead.index + 1) % MRK_PARSER_LOOKAHEAD_BUF_SIZE;
 }
 
 mrk_err mrk_parser_eat(mrk_token *out, mrk_parser *parser,
diff --git a/test/parser/compound.c b/test/parser/compound.c
new file mode 100644
index 0000000..ae1b16e
--- /dev/null
+++ b/test/parser/compound.c
@@ -0,0 +1,33 @@
+#include "test.h"
+
+#include "mrk/lexer.h"
+#include "mrk/parser_internal.h"
+
+#define LEXER_INIT() \
+  mrk_lexer *lxr; \
+  TEST_CHECK(mrk_lexer_init(&lxr) == mrk_err_ok)
+
+#define PARSER_INIT() \
+  mrk_parser *parser; \
+  TEST_CHECK(mrk_parser_init(&parser) == mrk_err_ok)
+
+#define PARSER_OPEN(buf) \
+  mrk_lexer *lxr; \
+  TEST_CHECK(mrk_lexer_init(&lxr) == mrk_err_ok); \
+  mrk_parser *parser; \
+  TEST_CHECK(mrk_parser_init(&parser) == mrk_err_ok); \
+  mrk_lexer_open(lxr, buf, 0); \
+  mrk_parser_open(parser, lxr)
+
+void test_parse_simple_header_paragraph() {
+  const char *buf = "# this is a header\n\nthis is a paragraph with a [link](https://example.com)";
+  PARSER_OPEN(buf);
+
+  mrk_ast_node *root;
+  TEST_CHECK(mrk_parser_parse(&root, parser) == mrk_err_ok);
+}
+
+TEST_LIST = {
+  { "parser simple header and paragraph", test_parse_simple_header_paragraph },
+  { NULL, NULL }
+};