diff --git a/src/parser/grammar_basic.c b/src/parser/grammar_basic.c
index b7f58bd..f0f96f9 100644
--- a/src/parser/grammar_basic.c
+++ b/src/parser/grammar_basic.c
@@ -68,8 +68,13 @@ struct ast *parse_list(struct lexer_context *ctx)
     token = PEEK_TOKEN();
     while (token->type == TOKEN_SEMICOLON)
     {
-        token = POP_TOKEN();
+        // Forward
+        POP_TOKEN();
         token = PEEK_TOKEN();
+
+        // TODO seems a little akward (not fully compliant with the grammar)
+        // but it's time consuming to rewrite to only cover edge cases.
+        // So it'll probably stay like that for now
         if (is_first(*token, RULE_AND_OR))
         {
             current_node = parse_and_or(ctx);
@@ -304,8 +309,26 @@ struct ast *parse_element(struct lexer_context *ctx)
     struct token *token = PEEK_TOKEN();
     if (token->type == TOKEN_WORD || token->type == TOKEN_ASSIGNMENT_WORD)
     {
-        token = POP_TOKEN();
-        return ast_create_word(token->data);
+        POP_TOKEN();
+
+        char *word = strdup(token->data);
+        if (word == NULL)
+        {
+            perror("Internal error: could not copy token data (is your memory "
+                   "full ?)");
+            return NULL;
+        }
+
+        struct ast *result = ast_create_word(word);
+        if (result == NULL)
+        {
+            perror("Internal error: could not create ast node (is your memory "
+                   "full ?)");
+            free(word);
+            return NULL;
+        }
+
+        return result;
     }
     else if (token->type == TOKEN_IONUMBER || is_token_redir(token))
     {
@@ -378,12 +401,15 @@ struct ast *parse_if_rule(struct lexer_context *ctx)
 
     // Condition content
     struct ast *condition_content = parse_compound_list(ctx);
+    if (condition_content == NULL)
+        return NULL;
+    token = PEEK_TOKEN();
 
     // Then keyword
-    token = PEEK_TOKEN();
     if (token->type != TOKEN_THEN)
     {
-        perror("Expected the 'then' keyword but token has different type");
+        perror("Syntax error: Expected the 'then' keyword but token has "
+               "different type");
         return err_if_rule(&condition_content, NULL, NULL);
     }
     POP_TOKEN();
@@ -394,9 +420,9 @@ struct ast *parse_if_rule(struct lexer_context *ctx)
     {
         return err_if_rule(&condition_content, &then_content, NULL);
     }
+    token = PEEK_TOKEN();
 
     struct ast *else_content = NULL;
-    token = PEEK_TOKEN();
     // Eventual else/elif clause(s)
     if (is_first(*token, RULE_ELSE_CLAUSE))
     {
@@ -405,10 +431,10 @@ struct ast *parse_if_rule(struct lexer_context *ctx)
         {
             return err_if_rule(&condition_content, &then_content, NULL);
         }
+        token = PEEK_TOKEN();
     }
 
     // Fi keyword
-    token = PEEK_TOKEN();
     if (token->type != TOKEN_FI)
     {
         perror("Expected the 'fi' keyword but token has different type");
@@ -437,7 +463,7 @@ struct ast *parse_compound_list(struct lexer_context *ctx)
     // Skip newlines
     while (token->type == TOKEN_NEWLINE)
     {
-        token = POP_TOKEN();
+        POP_TOKEN();
         token = PEEK_TOKEN();
     }
 
@@ -446,9 +472,9 @@ struct ast *parse_compound_list(struct lexer_context *ctx)
     if (current_cmd == NULL)
         return NULL;
     result_list = list_append(result_list, current_cmd);
+    token = PEEK_TOKEN();
 
     // Following commands
-    token = PEEK_TOKEN();
     while (token->type == TOKEN_SEMICOLON || token->type == TOKEN_NEWLINE)
     {
         POP_TOKEN();
@@ -457,7 +483,7 @@ struct ast *parse_compound_list(struct lexer_context *ctx)
         // Skip newlines
         while (token->type == TOKEN_NEWLINE)
         {
-            token = POP_TOKEN();
+            POP_TOKEN();
             token = PEEK_TOKEN();
         }
 
@@ -468,22 +494,21 @@ struct ast *parse_compound_list(struct lexer_context *ctx)
             if (current_cmd == NULL)
                 return NULL;
             result_list = list_append(result_list, current_cmd);
+            token = PEEK_TOKEN();
         }
-
-        token = PEEK_TOKEN();
     }
 
-    // Eventual semicolons
+    // Eventual semicolon
     if (token->type == TOKEN_SEMICOLON)
     {
-        token = POP_TOKEN();
+        POP_TOKEN();
         token = PEEK_TOKEN();
     }
 
     // Skip newlines
     while (token->type == TOKEN_NEWLINE)
     {
-        token = POP_TOKEN();
+        POP_TOKEN();
         token = PEEK_TOKEN();
     }
 
@@ -513,18 +538,31 @@ struct ast *parse_else_clause(struct lexer_context *ctx)
 
         // Then clause
         struct ast *then_content = parse_compound_list(ctx);
+        if (then_content == NULL)
+        {
+            ast_free(&condition);
+            return NULL;
+        }
+        token = PEEK_TOKEN();
 
         // Eventual else clause (recursive)
         struct ast *else_content = NULL;
-        token = PEEK_TOKEN();
         if (token->type == TOKEN_ELSE || token->type == TOKEN_ELIF)
         {
             else_content = parse_else_clause(ctx);
+            if (else_content == NULL)
+            {
+                ast_free(&then_content);
+                ast_free(&condition);
+                return NULL;
+            }
+        }
+        else
+        {
+            else_content = ast_create_void();
         }
 
-        struct ast *result =
-            ast_create_if(condition, then_content, else_content);
-        return result;
+        return ast_create_if(condition, then_content, else_content);
     }
 
     // Eventual else content
@@ -533,12 +571,15 @@ struct ast *parse_else_clause(struct lexer_context *ctx)
 
     if (token->type == TOKEN_ELSE)
     {
-        token = POP_TOKEN(); // eat else
+        token = POP_TOKEN();
         result = parse_compound_list(ctx);
+        if (result == NULL)
+            return NULL;
     }
-
-    if (result == NULL)
+    else
+    {
         result = ast_create_void();
+    }
 
     return result;
 }