c-preprocessor

commit f1b59fb58004653c7c58c1735112f318cd16f678
parent 58c8d34fa4a368d94b4c5544d5cde18281af2364
Author: quantumish <freifeld.david@gmail.com>
Date:   Mon, 19 Jun 2023 19:06:02 -0700

Proper proof of concept

Diffstat:
M
cpreprocessor/__init__.py
 | 
111
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----

1 file changed, 105 insertions(+), 6 deletions(-)
diff --git a/cpreprocessor/__init__.py b/cpreprocessor/__init__.py
@@ -3,6 +3,106 @@ import encodings
 from encodings import utf_8
 import io
 
+from dataclasses import dataclass
+import sys
+from collections import namedtuple
+import re
+
+a = """
+#define TESTING 1
+
+def myfunc():
+    return TESTING
+
+#ifdef TESTING
+def debug_func():
+    print("whee")
+    if TESTING:
+        print("whoo")
+#endif
+
+"""
+
+
+def handle_define(tokens, state):
+    if len(tokens) == 1:
+        print("Error: bare #define", file=sys.stderr)
+        exit(1)
+    if len(tokens) > 2:
+        state.defs[tokens[1]] = " ".join(tokens[2:])
+    else:
+        state.defs[tokens[1]] = ""
+
+def handle_ifdef(tokens, state):
+    if len(tokens) == 1:
+        print("Error: bare #ifdef", file=sys.stderr)
+        exit(1)
+
+    if tokens[1] not in state.defs:
+        state.skip = True
+
+
+def handle_endif(tokens, state):
+    skip = False
+        
+Directive = namedtuple("Directive", "name handler")
+
+handlers = [
+    Directive("#define", handle_define),
+    # Directive("#ifdef", handle_ifdef),
+    Directive("#endif", handle_endif)
+    # Directive("#ifndef", handle_ifndef)
+]
+
+def try_handle_directive(tokens, state):
+    if len(tokens) == 0: return False
+    for directive in handlers:
+        if tokens[0] == directive.name:
+            directive.handler(tokens, state)
+            del[state.lines[state.i]]
+            return True
+    return False
+
+@dataclass
+class State:
+    defs: dict
+    skip: bool
+    lines: list
+    i: int
+
+    def __init__(self, lines):
+        self.defs = {}
+        self.skip = False
+        self.lines = lines
+        self.i = 0
+
+def preprocess(code):
+    lines = code.split("\n")
+    state = State(lines)
+    while state.i < len(lines):
+        tokens = re.split("(?<=\S)\s+", state.lines[state.i])
+
+        if len(tokens) == 2 and tokens[0] == "#ifdef":
+            handle_ifdef(tokens, state)
+            del[state.lines[state.i]]
+            continue
+        
+        for j in range(len(tokens)):
+            for definition in state.defs: # GROSS
+                tokens[j] = tokens[j].replace(definition, state.defs[definition])                
+
+        if try_handle_directive(tokens, state):
+            continue
+
+        if state.skip:
+            del state.lines[state.i]
+            continue
+
+        state.lines[state.i] = " ".join(tokens)
+        state.i += 1
+
+    return "\n".join(lines)
+
 def encode(input_string):
     print(encoded_bytes)
     out = (input_string+"a").encode()
@@ -17,14 +117,12 @@ def decode(encoded_bytes):
 
 class IncrementalDecoder(utf_8.IncrementalDecoder):
     def decode(self, inp, final=False):
-        if inp != b"":
-            # NOTE: buffer MUST start with '\n'
-            self.buffer += b'\nprint("hi")'
+        self.buffer += inp
         if final:
             buff = self.buffer
             self.buffer = b""
             return super(IncrementalDecoder, self,).decode(
-                buff, final=True
+                preprocess(buff.decode()).encode(), final=True
             )
         else:
             return ""
@@ -37,10 +135,11 @@ class StreamReader(utf_8.StreamReader):
 
         
 def custom_search_function(encoding_name):
-    if encoding_name != "cprepross": return None
+    # print(encoding_name)
+    if encoding_name != "c_preprocessor": return None
     utf8=encodings.search_function('utf8')
     return codecs.CodecInfo(
-        name='cprepross',
+        name='c_preprocessor',
         encode = encode,
         decode = decode,
         incrementalencoder=utf8.incrementalencoder,