1 files changed, 60 insertions, 0 deletions
diff --git a/doc/tools/coqrst/notations/regexp.py b/doc/tools/coqrst/notations/regexp.py
new file mode 100644
index 00000000..ea820c71
--- /dev/null
+++ b/doc/tools/coqrst/notations/regexp.py
@@ -0,0 +1,60 @@
+##########################################################################
+##         #   The Coq Proof Assistant / The Coq Development Team       ##
+##  v      #   INRIA, CNRS and contributors - Copyright 1999-2018       ##
+## <O___,, #       (see CREDITS file for the list of authors)           ##
+##   \VV/  ###############################################################
+##    //   #    This file is distributed under the terms of the         ##
+##         #     GNU Lesser General Public License Version 2.1          ##
+##         #     (see LICENSE file for the text of the license)         ##
+##########################################################################
+"""An experimental visitor for ANTLR notation ASTs, producing regular expressions."""
+
+import re
+from io import StringIO
+
+from .parsing import parse
+from .TacticNotationsParser import TacticNotationsParser
+from .TacticNotationsVisitor import TacticNotationsVisitor
+
+class TacticNotationsToRegexpVisitor(TacticNotationsVisitor):
+    def __init__(self):
+        self.buffer = StringIO()
+
+    def visitRepeat(self, ctx:TacticNotationsParser.RepeatContext):
+        separator = ctx.ATOM()
+        repeat_marker = ctx.LGROUP().getText()[1]
+
+        self.buffer.write("(")
+        self.visitChildren(ctx)
+        self.buffer.write(")")
+
+        if repeat_marker in ["?", "*"]:
+            self.buffer.write("?")
+        elif repeat_marker in ["+", "*"]:
+            self.buffer.write("(")
+            self.buffer.write(r"\s*" + re.escape(separator.getText() if separator else " ") + r"\s*")
+            self.visitChildren(ctx)
+            self.buffer.write(")*")
+
+    def visitCurlies(self, ctx:TacticNotationsParser.CurliesContext):
+        self.buffer.write(r"\{")
+        self.visitChildren(ctx)
+        self.buffer.write(r"\}")
+
+    def visitAtomic(self, ctx:TacticNotationsParser.AtomicContext):
+        self.buffer.write(re.escape(ctx.ATOM().getText()))
+
+    def visitHole(self, ctx:TacticNotationsParser.HoleContext):
+        self.buffer.write("([^();. \n]+)") # FIXME could allow more things
+
+    def visitMeta(self, ctx:TacticNotationsParser.MetaContext):
+        self.buffer.write(re.escape(ctx.METACHAR().getText()[1:]))
+
+    def visitWhitespace(self, ctx:TacticNotationsParser.WhitespaceContext):
+        self.buffer.write(r"\s+")
+
+def regexpify(notation):
+    """Translate notation to a Python regular expression matching it"""
+    vs = TacticNotationsToRegexpVisitor()
+    vs.visit(parse(notation))
+    return vs.buffer.getvalue()