feat(lexer): implementing assignements

src/lexer/lexer.c

@@ -78,6 +78,21 @@ static bool update_lexing_mode(char *stream, ssize_t i,
     return *lexing_mode != mode_before_update;
 }
 
+/* @brief: updates the flags only_digits and equal_count
+ *         according to the character at stream[i].
+ */
+static void update_flags(char *stream, ssize_t i, struct lexer_context *ctx)
+{
+    if (stream[i] == '=')
+    {
+        ctx->equal_count++;
+    }
+    else if (!isdigit(stream[i]) && ctx->only_digits)
+    {
+        ctx->only_digits = false;
+    }
+}
+
 struct token *peek_token(struct lexer_context *ctx)
 {
     // we already created the upcoming token during the previous call to peek()
@@ -100,6 +115,7 @@ struct token *peek_token(struct lexer_context *ctx)
         if (!update_lexing_mode(stream, i, &lexing_mode)
             && lexing_mode == LEXER_NORMAL)
         {
+            update_flags(stream, i, ctx);
             if (is_special_char(stream, i))
             {
                 if (i == 0) // where we create spe_char token
@@ -121,7 +137,7 @@ struct token *peek_token(struct lexer_context *ctx)
         i++;
     }
 
-    struct token *tok = new_token(stream, i, ctx->only_digits);
+    struct token *tok = new_token(stream, i, ctx->only_digits, ctx->equal_count);
     // if token is comment, we don't want it
 
     if (tok->type == TOKEN_COMMENT)

src/lexer/lexer_utils.h

@@ -14,6 +14,9 @@ struct lexer_context
     // tells us if we only lexed digits in current token.
     bool only_digits;
 
+    // usefull to detect assignments, and syntax errors with '='.
+    int equal_count;
+
     struct token *previous_token;
     struct token *current_token;
 };
@@ -34,10 +37,13 @@ enum token_type
     // Blanks
     TOKEN_NULL = 0,
     TOKEN_EOF,
-    TOKEN_WORD,
     TOKEN_NEWLINE,
 
-    // SPecial characters
+    // words
+    TOKEN_WORD,
+    TOKEN_ASSIGNMENT_WORD,
+
+    // Special characters
     TOKEN_GRAVE,
     TOKEN_SEMICOLON,
     TOKEN_COMMENT,
@@ -87,12 +93,13 @@ struct token
  */
 bool is_special_char(char *stream, ssize_t i);
 
-/* @brief: return a newly allocated token, with the corresponding type.
+/* @brief: return a newly allocated token, with the type corresponding
+ *         to the context given in arguments.
  *         The data contains [size] char, starting from [begin].
  *
  * @return: NULL on error, a token otherwise.
  */
-struct token *new_token(char *begin, ssize_t size, bool only_digits);
+struct token *new_token(char *begin, ssize_t size, bool only_digits, int equal_count);
 
 /* @brief: frees the token given in argument
  */

src/parser/grammar_advanced.c

@@ -66,5 +66,17 @@ struct ast *parse_redirection(struct lexer_context *ctx)
 
 struct ast *parse_prefix(struct lexer_context *ctx)
 {
-    return parse_redirection(ctx);
+    struct token *token = TOKEN_PEEK();
+    if (token->type == TOKEN_ASSIGNMENT_WORD)
+    {
+        token = TOKEN_POP();
+        return ast_create_assignment_word(token->data);
+    }
+    else if (is_first(*token, RULE_REDIRECTION))
+        return parse_redirection(ctx);
+    else 
+    {
+        perror("Syntax error: expected a prefix (redirection or assignment)");
+        return NULL;
+    }
 }