From 7cb4b28da8df46443bb1aa336ccd94e497df8c48 Mon Sep 17 00:00:00 2001
From: Abdelrahman <said.abdelrahman89@gmail.com>
Date: Sun, 30 Jul 2023 19:18:10 +0100
Subject: [PATCH] Store the current character and add more handlers after the
 state transition

---
 src/lexer/lexer.c | 79 +++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 70 insertions(+), 9 deletions(-)

diff --git a/src/lexer/lexer.c b/src/lexer/lexer.c
index cca1c17..9e570cd 100644
--- a/src/lexer/lexer.c
+++ b/src/lexer/lexer.c
@@ -58,6 +58,7 @@ struct lexer_s {
   bool has_extra_token;
   token_t extra_token;
   dstr_t *error_message;
+  char current_char;
 };
 
 INTERNAL lexer_input_t char_type(char input);
@@ -78,6 +79,7 @@ INTERNAL void set_token(token_t *token, u64 line, u64 column, token_type type,
 INTERNAL void finalise_state_transition(lexer_t *lexer);
 INTERNAL void post_keyword(lexer_t *lexer);
 INTERNAL void set_numerical_token(lexer_t *lexer);
+INTERNAL void handle_string_end(lexer_t *lexer);
 
 INTERNAL lexer_state_t state_table[COUNT_LEXER_STATES][COUNT_LEXER_INPUTS] = {
 #include "lexer_state_transitions.table"
@@ -136,8 +138,6 @@ lex_result_t get_next_token(lexer_t *lexer, const char *text) {
 
   dstr_clear(lexer->current_string);
 
-  char c;
-
   while (lexer->cursor < lexer->text_length) {
     if (lexer->has_extra_token) {
       lexer->has_extra_token = false;
@@ -148,15 +148,15 @@ lex_result_t get_next_token(lexer_t *lexer, const char *text) {
       };
     }
 
-    c = lexer->text[(lexer->cursor)++];
+    lexer->current_char = lexer->text[(lexer->cursor)++];
 
-    lexer_input_t current_input = char_type(c);
+    lexer_input_t input = char_type(lexer->current_char);
 
-    lexer->next = state_table[lexer->current][current_input];
+    lexer->next = state_table[lexer->current][input];
 
     finalise_state_transition(lexer);
 
-    if (current_input == LEXER_INPUT_NEWLINE) {
+    if (input == LEXER_INPUT_NEWLINE) {
       ++(lexer->line);
       lexer->column = 0;
     } else {
@@ -437,16 +437,53 @@ void set_token(token_t *token, u64 line, u64 column, token_type type,
 void finalise_state_transition(lexer_t *lexer) {
   switch (lexer->next) {
   case LEXER_STATE_OBJECT_START:
+    lexer->token_ready = true;
+    set_token(&(lexer->token), lexer->line, lexer->column, TK_L_BRACE,
+              (token_value_t){0});
+
     stack_push(&(lexer->stack), LEXER_STATE_OBJECT);
 
     lexer->next = LEXER_STATE_OBJECT;
 
+    break;
+  case LEXER_STATE_OBJECT_END:
     break;
   case LEXER_STATE_ARRAY_START:
+    lexer->token_ready = true;
+    set_token(&(lexer->token), lexer->line, lexer->column, TK_L_BRACKET,
+              (token_value_t){0});
+
     stack_push(&(lexer->stack), LEXER_STATE_ARRAY);
 
     lexer->next = LEXER_STATE_ARRAY;
 
+    break;
+  case LEXER_STATE_ARRAY_END:
+    break;
+  case LEXER_STATE_KEY:
+    if (lexer->current == LEXER_STATE_OBJECT) {
+      stack_push(&(lexer->stack), LEXER_STATE_KEY);
+
+      lexer->next = LEXER_STATE_STRING;
+    }
+
+    break;
+  case LEXER_STATE_KEY_END:
+    lexer->next = LEXER_STATE_VALUE;
+
+    break;
+  case LEXER_STATE_STRING:
+  case LEXER_STATE_ESCAPE_SEQUENCE:
+  case LEXER_STATE_UNICODE_HEX1:
+  case LEXER_STATE_UNICODE_HEX2:
+  case LEXER_STATE_UNICODE_HEX3:
+  case LEXER_STATE_UNICODE_HEX4:
+    dstr_append(&(lexer->current_string), lexer->current_char);
+
+    break;
+  case LEXER_STATE_STRING_END:
+    handle_string_end(lexer);
+
     break;
   case LEXER_STATE_TRUE:
   case LEXER_STATE_FALSE:
@@ -471,7 +508,16 @@ void finalise_state_transition(lexer_t *lexer) {
 
     break;
   case LEXER_STATE_NUMBER_END:
-    set_numerical_token(lexer);
+    switch (lexer->current) {
+    case LEXER_STATE_NUMBER:
+    case LEXER_STATE_FRACTION:
+    case LEXER_STATE_POWER:
+      set_numerical_token(lexer);
+
+      break;
+    default:
+      break;
+    }
 
     break;
   }
@@ -513,14 +559,14 @@ void post_keyword(lexer_t *lexer) {
 
     break;
   default:
-    lexer->current = LEXER_STATE_ERROR;
+    lexer->next = LEXER_STATE_ERROR;
 
     return;
   }
 
   lexer->token_ready = true;
 
-  lexer->current = LEXER_STATE_KEYWORD_END;
+  lexer->next = LEXER_STATE_KEYWORD_END;
 }
 
 void set_numerical_token(lexer_t *lexer) {
@@ -532,6 +578,21 @@ void set_numerical_token(lexer_t *lexer) {
   set_token(&(lexer->token), lexer->line, column, token.type, token.value);
 }
 
+void handle_string_end(lexer_t *lexer) {
+  lexer_state_t string_type = lexer->stack.stack[lexer->stack.size - 1];
+
+  lexer->token_ready = true;
+  token_t *token = &(lexer->token);
+  u64 column = lexer->column - dstr_length(lexer->current_string);
+  token_value_t value = {.string = dstr_to_cstr(lexer->current_string)};
+
+  if (string_type == LEXER_STATE_KEY) {
+    set_token(token, lexer->line, column, TK_STR_KEY, value);
+  } else if (string_type == LEXER_STATE_VALUE) {
+    set_token(token, lexer->line, column, TK_STR_VAL, value);
+  }
+}
+
 void lexer_state_machine(lexer_t *lexer, char input) {
   switch (lexer->current) {
   case LEXER_STATE_START: