Concrete syntax no longer indentation-based (nightmare to parse). Add indented multi-line code terminals.

concrete_syntax/common.py

@@ -0,0 +1,16 @@
+def indent(multiline_string, how_much):
+    lines = multiline_string.split('\n')
+    return '\n'.join([' '*how_much+l for l in lines])
+
+def display_value(val: any, type_name: str, indentation=0):
+    if type_name == "ActionCode":
+        if '\n' in val:
+            return '```\n'+indent(val, indentation+4)+'\n'+' '*indentation+'```'
+        else:
+            return '`'+val+'`'
+    elif type_name == "String":
+        return '"'+val+'"'
+    elif type_name == "Integer" or type_name == "Boolean":
+        return str(val)
+    else:
+        raise Exception("don't know how to display value" + type_name)