From 4c4f0695b12c5faabfe7c3076e4b96151bb24282 Mon Sep 17 00:00:00 2001
From: Iskander Sharipov <quasilyte@gmail.com>
Date: Thu, 20 Jan 2022 17:11:32 +0300
Subject: [PATCH] dsl: add submatches experimental API

Refs #28
---
 dsl/dsl.go | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/dsl/dsl.go b/dsl/dsl.go
index 76d89d3d..c82781ab 100644
--- a/dsl/dsl.go
+++ b/dsl/dsl.go
@@ -154,6 +154,16 @@ type Var struct {
 // For example, `VarFilterContext.Type` is mapped to `Var.Type`.
 func (Var) Filter(pred func(*VarFilterContext) bool) bool { return boolResult }
 
+// Contains runs a sub-search from a given pattern using the captured
+// vars from the original pattern match.
+//
+// For example, given the Match(`$lhs = append($lhs, $x)`) pattern,
+// we can do m["lhs"].Contains(`$x`) and learn whether $lhs contains
+// $x as its sub-expression.
+//
+// Experimental: this function is not part of the stable API.
+func (Var) Contains(pattern string) bool { return boolResult }
+
 // MatchedNode represents an AST node associated with a named submatch.
 type MatchedNode struct{}