Add concrete syntax for class diagrams + example (woods2.py)

concrete_syntax/common.py

@@ -1,3 +1,5 @@
+from lark import Transformer
+
 def indent(multiline_string, how_much):
     lines = multiline_string.split('\n')
     return '\n'.join([' '*how_much+l for l in lines])
@@ -14,3 +16,42 @@ def display_value(val: any, type_name: str, indentation=0):
         return str(val)
     else:
         raise Exception("don't know how to display value" + type_name)
+
+
+# internal use only
+# just a dumb wrapper to distinguish between code and string
+class _Code:
+   def __init__(self, code):
+      self.code = code
+
+class TBase(Transformer):
+
+    def IDENTIFIER(self, token):
+        return str(token)
+    
+    def INT(self, token):
+        return int(token)
+
+    def BOOL(self, token):
+        return token == "True"
+
+    def STR(self, token):
+        return str(token[1:-1]) # strip the "" or ''
+
+    def CODE(self, token):
+        return _Code(str(token[1:-1])) # strip the ``
+
+    def INDENTED_CODE(self, token):
+        skip = 4 # strip the ``` and the following newline character
+        space_count = 0
+        while token[skip+space_count] == " ":
+            space_count += 1
+        lines = token.split('\n')[1:-1]
+        for line in lines:
+            if len(line) >= space_count and line[0:space_count] != ' '*space_count:
+                raise Exception("wrong indentation of INDENTED_CODE")
+        unindented_lines = [l[space_count:] for l in lines]
+        return _Code('\n'.join(unindented_lines))
+
+    def literal(self, el):
+        return el[0]