From 7a4e03657e229ca60ec2fabd5eca9fc2eaa9271e Mon Sep 17 00:00:00 2001
From: Drew Lipiecki <alipiecki@apple.com>
Date: Wed, 8 Feb 2017 13:25:41 -0800
Subject: [PATCH] [gyb] added feature to gyb.py to search for an process a new
 template tag, when encountered in AST it is processed in line

---
 utils/gyb.py | 37 +++++++++++++++++++++++++++++++------
 1 file changed, 31 insertions(+), 6 deletions(-)

diff --git a/utils/gyb.py b/utils/gyb.py
index 8f26694484c78..0acfce33168fb 100755
--- a/utils/gyb.py
+++ b/utils/gyb.py
@@ -50,9 +50,8 @@ def split_lines(s):
     """
     return [l + '\n' for l in s.split('\n')]
 
-
-# text on a line up to the first '$$', '${', or '%%'
-literalText = r'(?: [^$\n%] | \$(?![${]) | %(?!%) )*'
+# text on a line up to the first '$$', '${', <{, or '%%'
+literalText = r'(?: [^$\n%] | \$(?![${]) | \<(?![<{]) | %(?!%) )*'
 
 # The part of an '%end' line that follows the '%' sign
 linesClose = r'[\ \t]* end [\ \t]* (?: \# .* )? $'
@@ -85,6 +84,10 @@ def split_lines(s):
 | (?P<substitutionOpen> \$\{ )
   [^}]* \} # Absorb
 
+# Embedded Templates
+| (?P<templateOpen> \<\{ )
+  [^}]* \}
+
 # %% and $$ are literal % and $ respectively
 | (?P<symbol>[$%]) (?P=symbol)
 
@@ -503,8 +506,11 @@ def token_generator(self, base_tokens):
                     if not m2:
                         raise ValueError("Invalid block closure")
                     next_pos = m2.end(0)
+                elif (kind == 'substitutionOpen'):
+                    # skip past the closing '}'
+                    next_pos = close_pos + 1
                 else:
-                    assert kind == 'substitutionOpen'
+                    assert kind == 'templateOpen'
                     # skip past the closing '}'
                     next_pos = close_pos + 1
 
@@ -622,6 +628,8 @@ def __init__(self, context):
         while context.token_kind and not context.close_lines:
             if context.token_kind == 'literal':
                 node = Literal
+            elif context.token_kind == 'templateOpen':
+                node = Template
             else:
                 node = Code
             self.children.append(node(context))
@@ -745,6 +753,25 @@ def __str__(self, indent=''):
             ) + '\n' + indent + '}'
         return s + self.format_children(indent)
 
+class Template(ASTNode):
+
+    """An AST node that is evaluated as an embedded Template"""
+
+    children = ()
+    filename = None
+
+    def __init__(self, context):
+        self.filename = context.filename
+        self.template_filename = os.path.dirname(context.filename) + '/' + context.code_text
+        self.children += (Block(ParseContext(self.template_filename)),)
+        context.next_token()
+
+    def execute(self, context):
+        for x in self.children:
+            x.execute(context)
+
+    def __str__(self, indent=''):
+        return self.filename
 
 def expand(filename, line_directive=_default_line_directive, **local_bindings):
     r"""Return the contents of the givepn template file, executed with the given
@@ -803,7 +830,6 @@ def expand(filename, line_directive=_default_line_directive, **local_bindings):
         finally:
             os.chdir(d)
 
-
 def parse_template(filename, text=None):
     r"""Return an AST corresponding to the given template file.
 
@@ -1225,6 +1251,5 @@ def succ(a):
 
     args.target.write(execute_template(ast, args.line_directive, **bindings))
 
-
 if __name__ == '__main__':
     main()