fix: on error parsing, fall back to "raw" prompt

Closes damian0815#69

src/compel/compel.py

@@ -4,6 +4,7 @@
 import torch
 from torch import Tensor
 from transformers import CLIPTokenizer, CLIPTextModel
+from pyparsing.exceptions import ParseException
 
 from . import cross_attention_control
 from .conditioning_scheduler import ConditioningScheduler, StaticConditioningScheduler
@@ -155,7 +156,10 @@ def parse_prompt_string(cls, prompt_string: str) -> Conjunction:
         Parse the given prompt string and return a structured Conjunction object that represents the prompt it contains.
         """
         pp = PromptParser()
-        conjunction = pp.parse_conjunction(prompt_string)
+        try:
+            conjunction = pp.parse_conjunction(prompt_string)
+        except ParseException:
+            return Conjunction(prompts=[FlattenedPrompt([(prompt_string, 1.0)])], weights=[1.0])
         return conjunction
 
     def describe_tokenization(self, text: str) -> List[str]: