Add forgotten jwutils/CppState.py

Signed-off-by: Jan Lindemann <jan@janware.com>

tools/python/jwutils/CppState.py

@@ -0,0 +1,102 @@
+class CppState: # export
+
+    def __init__(self):
+        self.__pair_square = ['[', ']']
+        self.__pair_curly = ['{', '}']
+        self.__pair_ext = ['<', '>']
+        self.__pair_paren = ['(', ')']
+        self.__pair_c_comment = ['/*', '*/']
+        self.__pair_special = ['?', '?']
+        self.reset()
+
+    def reset(self):
+        self.curly = 0
+        self.square = 0
+        self.ext = 0
+        self.paren = 0
+        self.in_c_comment = False
+        self.in_cpp_comment = False
+        self.in_special = False
+        self.rule = []
+        self.rules = []
+        self.things = []
+
+    def optional(self):
+        return self.square != 0 or self.curly != 0
+
+    def update(self, tok, line):
+        if not self.in_comment():
+            if tok == '[':
+                self.square += 1
+                self.things.append(self.__pair_square)
+            elif tok == ']':
+                self.square -= 1
+                assert(self.things.pop() == self.__pair_square)
+            elif tok == '{':
+                self.curly += 1
+                self.things.append(self.__pair_curly)
+            elif tok == '}':
+                self.curly -= 1
+                assert(self.things.pop() == self.__pair_curly)
+            elif tok == '(':
+                self.paren += 1
+                self.things.append(self.__pair_paren)
+            elif tok == ')':
+                self.paren -= 1
+                assert(self.things.pop() == self.__pair_paren)
+            elif tok == '<':
+                self.ext += 1
+                self.things.append(self.__pair_ext)
+            elif tok == '>':
+                self.ext -= 1
+                assert(self.things.pop() == self.__pair_ext)
+            elif tok == '?':
+                if not self.in_special:
+                    self.in_special = True
+                    self.things.append(self.__pair_special)
+                else:
+                    self.in_special = False
+                    assert(self.things.pop() == self.__pair_special)
+            elif tok == '/*':
+                self.in_c_comment = True
+                self.things.append(self.__pair_c_comment)
+            elif tok == '*/':
+                raise Exception("Unmatched closing C-style comment mark", tok, "in line", line)
+        else:
+            if self.in_cpp_comment:
+                if tok == '\n':
+                    self.in_cpp_comment = False
+                    return
+            if tok == '/*':
+                raise Exception("Nested C-style comment", tok, "in line", line)
+            elif tok == '*/':
+                assert(self.things.pop() == self.__pair_c_comment)
+                self.in_c_comment = False
+
+        if self.curly < 0 or self.square < 0 or self.ext < 0 or self.paren < 0:
+            raise Exception("Unbalanced BNF bracket", tok, "in line", line)
+        return self.optional()
+
+    def in_list(self):
+        return self.curly > 0
+
+    def in_option(self):
+        return self.square > 0
+
+    def in_paren(self):
+        return self.paren > 0
+
+    def in_ext(self):
+        return self.ext > 0
+
+    def in_comment(self):
+        return self.in_c_comment or self.in_cpp_comment
+
+    def in_something(self):
+        if len(self.things) == 0:
+            return None
+        return self.things[-1]
+
+    def is_optional(self):
+        return self.in_list() or self.in_option()
+