fix invalid syntax not being called on an invalid assignment

src/parser/assign/assign.c

@@ -8,26 +8,20 @@
 ParsedValue *parse_assign(char *file, DArray *parsed, DArray *tokens,
                           ParsedValue *assign_to, size_t *index) {
   Token *token = darray_get(tokens, *index);
+  switch (assign_to->type) {
+    case AST_IDENTIFIER:
+    case AST_ASSIGN:
+      break;
+    default:
+      fprintf(stderr, "%s:%u:%u error: can't assign to %s\n", file, token->line,
+              token->column, ValueTypeNames[assign_to->type]);
+      exit(EXIT_FAILURE);
+  }
   ParsedAssign *assign = malloc(sizeof(ParsedAssign));
   assign->to = assign_to;
   assign->type = token->type;
   (*index)++;
   token = darray_get(tokens, *index);
-  switch (token->type) {
-  case TOKEN_ASSIGN:
-  case TOKEN_ASSIGN_CARET:
-  case TOKEN_ASSIGN_FLOORDIV:
-  case TOKEN_ASSIGN_MINUS:
-  case TOKEN_ASSIGN_MODULO:
-  case TOKEN_ASSIGN_PLUS:
-  case TOKEN_ASSIGN_SLASH:
-  case TOKEN_ASSIGN_STAR:
-    fprintf(stderr, "%s:%u:%u error: invalid syntax\n", file, token->line,
-            token->column);
-    exit(EXIT_FAILURE);
-  default:
-    break;
-  }
   assign->from = parse_token(file, parsed, tokens, index, true);
   ParsedValue *parsedValue = malloc(sizeof(ParsedValue));
   parsedValue->type = AST_ASSIGN;

src/parser/parser.c

@@ -10,6 +10,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+const char *ValueTypeNames[] = {"string", "assign", "identifier"};
+
 ParsedValue *parse_token(char *file, DArray *parsed, DArray *tokens,
                          size_t *index, bool inline_flag) {
   Token *token = darray_get(tokens, *index);
@@ -34,6 +36,26 @@ ParsedValue *parse_token(char *file, DArray *parsed, DArray *tokens,
     fprintf(stderr, "%s:%u:%u error: invalid indentation\n", file, token->line,
             token->column);
     exit(EXIT_FAILURE);
+  case TOKEN_IDENTIFIER:;
+    ParsedValue *assign_to = parse_identifier(token);
+    (*index)++;
+    if (*index >= tokens->size)
+      return assign_to;
+    token = darray_get(tokens, *index);
+    switch (token->type) {
+    case TOKEN_ASSIGN:
+    case TOKEN_ASSIGN_CARET:
+    case TOKEN_ASSIGN_FLOORDIV:
+    case TOKEN_ASSIGN_MINUS:
+    case TOKEN_ASSIGN_MODULO:
+    case TOKEN_ASSIGN_PLUS:
+    case TOKEN_ASSIGN_SLASH:
+    case TOKEN_ASSIGN_STAR:;
+      DArray slice = darray_slice(parsed, parsed->size, parsed->size);
+      return parse_assign(file, &slice, tokens, assign_to, index);
+    default:
+      return assign_to;
+    }
   case TOKEN_ASSIGN:
   case TOKEN_ASSIGN_CARET:
   case TOKEN_ASSIGN_FLOORDIV:
@@ -42,19 +64,9 @@ ParsedValue *parse_token(char *file, DArray *parsed, DArray *tokens,
   case TOKEN_ASSIGN_PLUS:
   case TOKEN_ASSIGN_SLASH:
   case TOKEN_ASSIGN_STAR:
-    if (parsed->size == 0) {
-      fprintf(stderr, "%s:%u:%u error: syntax error\n", file, token->line,
-              token->column);
-      exit(EXIT_FAILURE);
-    }
-    ParsedValue *assign_to = malloc(sizeof(ParsedValue));
-    memcpy(assign_to, darray_get(parsed, parsed->size - 1),
-           sizeof(ParsedValue));
-    darray_resize(parsed, parsed->size - 1);
-    return parse_assign(file, parsed, tokens, assign_to, index);
-  case TOKEN_IDENTIFIER:
-    (*index)++;
-    return parse_identifier(token);
+    fprintf(stderr, "%s:%u:%u error: syntax error\n", file, token->line,
+            token->column);
+    exit(EXIT_FAILURE);
   default:
     fprintf(stderr, "Panic: unreachable\n");
     exit(EXIT_FAILURE);

src/parser/parser.h

@@ -10,9 +10,11 @@ typedef struct LinkedList LinkedList;
 typedef enum {
   AST_STRING,
   AST_ASSIGN,
-  AST_IDENTIFIER,
+  AST_IDENTIFIER
 } ValueType;
 
+extern const char* ValueTypeNames[];
+
 typedef struct {
   ValueType type;
   void *data;