feat+fix: make compiler STRONGAAA

- FEAT: add source code length field in `fzl_reader_t` struct
- FIX: check name, lpair (lparen) and rpair (rparen) when lexing call
- FIX: check string literal termination
- FIX: increment position even on empty string to prevent infinite
lexing loop
- FIX: add string terminator in `fzl_mktoken` when allocating space for
string value
- FIX: add check for errors in recursevly called `walk`
- FIX: change source code holder from stack-stored `char[8192]` to
dynamically allocated with actual file size holder
- FIX: correct constant hasing util to hash actual string value instead
of link

src/compiler/fzl_reader.c

@@ -1,4 +1,5 @@
 #include <compiler/fzl_reader.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -16,6 +17,7 @@ fzl_reader_t *fzl_mkreader(char *source)
   reader->first = first_node;
   reader->last = first_node;
   reader->source = source;
+  reader->size = strlen(source);
   reader->position = 0;
   reader->at_end = true;
 
@@ -60,18 +62,27 @@ fzl_token_t *parse_string_literal(fzl_reader_t *reader)
     return NULL;
 
   char open_symbol = reader->source[lpos];
+  char close_symbol = '\0';
 
   do
   {
     lpos++;
     size++;
-  } while (reader->source[lpos] != open_symbol);
+
+    if (reader->source[lpos] == open_symbol)
+      close_symbol = open_symbol;
+
+  } while (reader->source[lpos] != open_symbol && lpos < reader->size);
   size++;
 
+  if (close_symbol != open_symbol)
+    return NULL;
+
   if (size == 2)
   {
     fzl_token_t *tok = fzl_mktoken(FZL_TOKTYPE_STR_LITERAL, reader->position,
                                    reader->position + 1, "", 0);
+    reader->position += 2;
     return tok;
   }
 
@@ -88,8 +99,7 @@ fzl_token_t *parse_string_literal(fzl_reader_t *reader)
 
 int fzl_read(fzl_reader_t *reader)
 {
-  const size_t len = strlen(reader->source);
-  if (reader->position >= len)
+  if (reader->position >= reader->size)
     return 0;
 
   do
@@ -139,8 +149,7 @@ int fzl_read(fzl_reader_t *reader)
           linepos++;
       }
 
-      sprintf(last_err, "error parsing token (position %ld of line %ld)", line,
-              linepos);
+      sprintf(last_err, "cannot parse token (%ld:%ld)", line, linepos);
       return -1;
     }
 
@@ -149,7 +158,7 @@ int fzl_read(fzl_reader_t *reader)
 
     reader->last->next = tok_node;
     reader->last = tok_node;
-  } while (reader->position < len);
+  } while (reader->position < reader->size);
 
   reader->at_end = true;
   return 0;