1 files changed, 31 insertions, 0 deletions
diff --git a/users/wpcarro/scratch/simple-select/parser.py b/users/wpcarro/scratch/simple-select/parser.py
new file mode 100644
index 000000000000..d26f970e57a2
--- /dev/null
+++ b/users/wpcarro/scratch/simple-select/parser.py
@@ -0,0 +1,31 @@
+class Parser(object):
+    def __init__(self, tokens):
+        self.tokens = tokens
+        self.i = 0
+
+    def exhausted(self):
+        return self.i >= len(self.tokens)
+
+    def peek(self, n=0):
+        return self.tokens[self.i + n]
+
+    def advance(self):
+        if not self.exhausted():
+            self.i += 1
+        return self.peek(n=-1)
+
+    def match(self, xs):
+        if self.peek() in xs:
+            self.advance()
+            return True
+        return False
+
+    def test(self, predicate):
+        return predicate(self.tokens, self.i)
+
+    def expect(self, predicate):
+        if self.exhausted():
+            raise Exception("Unexpected EOL")
+        if predicate(self.peek()):
+            return self.advance()
+        raise Exception("Unexpected token: \"{}\"".format(self.peek()))