[llvm] [llvm] Add a tool to check mustache compliance against the public spec (PR #142813)

[Nikita Popov via llvm-commits]

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+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Simple drivers to test the mustache spec found at
+// https://github.com/mustache/
+//
+// It is used to verify that the current implementation conforms to the spec.
+// Simply download the spec and pass the test files to the driver.
+//
+// The current implementation only supports non-optional parts of the spec, so
+// we do not expect any of the dynamic-names, inheritance, or lambda tests to
+// pass. Additionally, Triple Mustache is not supported, so we expect the
+// following tests to fail:
+//    Triple Mustache
+//    Triple Mustache Integer Interpolation
+//    Triple Mustache Decimal Interpolation
+//    Triple Mustache Null Interpolation
+//    Triple Mustache Context Miss Interpolation
+//    Dotted Names - Triple Mustache Interpolation
+//    Implicit Iterators - Triple Mustache
+//    Triple Mustache - Surrounding Whitespace
+//    Triple Mustache - Standalone
+//    Triple Mustache With Padding
+//    Standalone Indentation
+//    Implicit Iterator - Triple mustache
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nikic wrote:

As previously mentioned, I think it would be great to include this list directly in the tool so the user doesn't have to manually check which failures are expected and which aren't.

https://github.com/llvm/llvm-project/pull/142813