1 files changed, 75 insertions, 0 deletions
diff --git a/abdl/_parser.py b/abdl/_parser.py
new file mode 100644
index 0000000..3e179a2
--- /dev/null
+++ b/abdl/_parser.py
@@ -0,0 +1,75 @@
+# This file is part of A Boneless Datastructure Language
+# Copyright (C) 2020  Soni L.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import pyparsing
+
+from abdl import exceptions
+from abdl import _vm
+
+def _build_syntax():
+    # pylint: disable=protected-access
+    from pyparsing import Suppress, Literal, Forward, CharsNotIn, StringEnd, Combine, Optional, Group, Word, srange, Empty
+
+    subtree = Forward()
+
+    skippable = Optional("?", default="")
+
+    escape_char = Literal("%")
+    str_token = Literal("'")
+    re_token = Literal("/")
+
+    unexpected_token = CharsNotIn("", exact=1).setParseAction(exceptions.PatternError._unexpected_tok)
+    unexpected_end = StringEnd().setParseAction(exceptions.PatternError._unexpected_tok)
+
+    str_literal = (Combine(Suppress(str_token)
+            + (Suppress(escape_char) + (str_token | escape_char) | escape_char + CharsNotIn("", exact=1).setParseAction(exceptions.PatternError._str_escape) | CharsNotIn("%'"))[...]
+            + (Suppress(str_token) | StringEnd().setParseAction(exceptions.PatternError._str_end))) + skippable)
+    str_literal.setParseAction(lambda toks: [_vm.StringKey(toks)])
+
+    re_literal = (Combine(Suppress(re_token)
+            + (Suppress(escape_char) + (re_token | escape_char) | escape_char + CharsNotIn("", exact=1).setParseAction(exceptions.PatternError._re_escape) | CharsNotIn("%/"))[...]
+            + (Suppress(re_token) | StringEnd().setParseAction(exceptions.PatternError._re_end))) + skippable)
+    re_literal.setParseAction(lambda toks: [_vm.RegexKey(toks)])
+
+    arrow = Literal("->")
+    arrow.setParseAction(lambda: [_vm.Arrow()])
+
+    identifier = Word(srange("[A-Za-z_]"), srange("[A-Za-z0-9_]"))
+    identifier.setParseAction(lambda toks: [_vm.Ident(toks)])
+
+    parameter = (Suppress("$") + skippable + identifier)
+    parameter.setParseAction(lambda toks: [_vm.Param(toks)])
+
+    type_ = (Suppress(":") + skippable + Suppress("$") + identifier)
+    type_.setParseAction(lambda toks: [_vm.ApplyPredicate(toks)])
+
+    # support for objects-as-keys
+    keysubtree = (Suppress("[") + Group(type_[...] + subtree) + (Suppress("]") | unexpected_token | unexpected_end) + skippable)
+    keysubtree.setParseAction(lambda toks: [_vm.KeySubtree(toks)])
+
+    # represents key matching - switches from "key" to "value"
+    tag = (identifier + Optional(parameter | str_literal | re_literal | keysubtree) | parameter | str_literal | re_literal | keysubtree) + type_[...] + Empty().setParseAction(lambda: [_vm.End()])
+
+    # multiple value matching
+    valuesubtree = (Suppress("(") + Group(subtree) + (Suppress(")") | unexpected_token | unexpected_end) + Optional("?", default=""))
+    valuesubtree.setParseAction(lambda toks: [_vm.ValueSubtree(toks)])
+
+    # arrow and tag, value subtree
+    subtree <<= (arrow + tag)[...] + (valuesubtree + Empty().setParseAction(lambda: [_vm.End()]))[...]
+
+    return ((subtree | unexpected_token) + StringEnd()).parseWithTabs()
+
+BUILT_SYNTAX = _build_syntax()