Updated README about syntax highlighting for intellij

README.md

@@ -44,6 +44,7 @@ Lark provides syntax highlighting for its grammar files (\*.lark):
 
 - [Sublime Text & TextMate](https://github.com/lark-parser/lark_syntax)
 - [vscode](https://github.com/lark-parser/vscode-lark)
+- [Intellij & PyCharm](https://github.com/lark-parser/intellij-syntax-highlighting)
 
 ### Clones
 

docs/index.md

@@ -24,6 +24,7 @@ $ pip install lark-parser
 
 - [Sublime Text & TextMate](https://github.com/lark-parser/lark_syntax)
 - [Visual Studio Code](https://github.com/lark-parser/vscode-lark) (Or install through the vscode plugin system)
+- [Intellij & PyCharm](https://github.com/lark-parser/intellij-syntax-highlighting)
 
 -----
 

lark/lark.py

@@ -172,6 +172,8 @@ class Lark(Serialize):
 
         cache_fn = None
         if self.options.cache:
+            if self.options.parser != 'lalr':
+                raise NotImplementedError("cache only works with parser='lalr' for now")
             if isinstance(self.options.cache, STRING_TYPE):
                 cache_fn = self.options.cache
             else: