Begin source generation.

Start out easy by emiting an opcodes.rs file containing an opcode enumeration.

meta/srcgen.py

@@ -0,0 +1,73 @@
+"""
+Source code generator.
+
+The `srcgen` module contains generic helper routines and classes for generating
+source code.
+
+"""
+
+import sys
+import os
+
+class Formatter(object):
+    """
+    Source code formatter class.
+
+    - Collect source code to be written to a file.
+    - Keep track of indentation.
+
+    Indentation example:
+
+        >>> f = Formatter()
+        >>> f.line('Hello line 1')
+        >>> f.writelines()
+        Hello line 1
+        >>> f.indent_push()
+        >>> f.comment('Nested comment')
+        >>> f.indent_pop()
+        >>> f.line('Back again')
+        >>> f.writelines()
+        Hello line 1
+          // Nested comment
+        Back again
+
+    """
+
+    shiftwidth = 2
+
+    def __init__(self):
+        self.indent = ''
+        self.lines = []
+
+    def indent_push(self):
+        """Increase current indentation level by one."""
+        self.indent += ' ' * self.shiftwidth
+
+    def indent_pop(self):
+        """Decrease indentation by one level."""
+        assert self.indent != '', 'Already at top level indentation'
+        self.indent = self.indent[0:-self.shiftwidth]
+
+    def line(self, s):
+        """And an indented line."""
+        self.lines.append('{}{}\n'.format(self.indent, s))
+
+    def writelines(self, f=None):
+        """Write all lines to `f`."""
+        if not f:
+            f = sys.stdout
+        f.writelines(self.lines)
+
+    def update_file(self, filename, directory):
+        if directory is not None:
+            filename = os.path.join(directory, filename)
+        with open(filename, 'w') as f:
+            self.writelines(f)
+
+    def comment(self, s):
+        """Add a comment line."""
+        self.line('// ' + s)
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod()