Parametrize code generation actions from the command line

src/ifcexpressparser/README.txt

@@ -2,10 +2,11 @@ This folder contains Python code to generate C++ type information based on an
 Express schema. In particular is has only been tested using recent version of
 the IFC schema and will most likely fail on any other Express schema.
 
-The code can be invoked in the following way and results in two header files
+The code can be invoked in the following way and results in several code outputs
-and a single implementation file named according to the schema name in the 
+named according to the schema name in the Express file. A python 3 interpreter
-Express file. A python 3 interpreter with the pyparsing [1] library is required.
+with the pyparsing [1] library is required.
 
-$ python bootstrap.py express.bnf > express_parser.py && python express_parser.py IFC2X3_TC1.exp
+$ python bootstrap.py express.bnf > express_parser.py
+$ python express_parser.py IFC2X3_TC1.exp header implementation schema_class definitions
 
 [1] http://pyparsing.wikispaces.com/Download+and+Installation

src/ifcexpressparser/bootstrap.py

@@ -198,15 +198,10 @@ else:
     with open(cache_file, "wb") as f:
         pickle.dump(mapping, f, protocol=0)    
 
-import header
+import importlib
-import implementation
+for output in sys.argv[2:]:
-import schema_class
+    mdl = importlib.import_module(output)
-import definitions
+    mdl.Generator(mapping).emit()
-
-header.Header(mapping).emit()
-implementation.Implementation(mapping).emit()
-schema_class.SchemaClass(mapping).emit()
-definitions.Definitions(mapping).emit()
 
 sys.stdout.write(schema.name)
 """%('\n    '.join(statements)))

src/ifcexpressparser/definitions.py

@@ -64,3 +64,5 @@ class Definitions(codegen.Base):
 
     def __repr__(self):
         return self.str
+
+Generator = Definitions

src/ifcexpressparser/header.py

@@ -145,3 +145,5 @@ class Header(codegen.Base):
         
     def __repr__(self):
         return self.str
+
+Generator = Header

src/ifcexpressparser/implementation.py

@@ -257,3 +257,6 @@ class Implementation(codegen.Base):
         
     def __repr__(self):
         return self.str
+
+
+Generator = Implementation