[clang-tools-extra] [llvm] [llvm] add support for mustache templating language (PR #105893)

[via cfe-commits]

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@@ -0,0 +1,189 @@
+//===--- Mustache.h ---------------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Implementation of the Mustache templating language supports version 1.4.2
+// currently relies on llvm::json::Value for data input
+// see the Mustache spec for more information
+// (https://mustache.github.io/mustache.5.html).
+//
+// Current Features Supported:
+// - Variables
+// - Sections
+// - Inverted Sections
+// - Partials
+// - Comments
+// - Lambdas
+// - Unescaped Variables
+//
+// Features Not Supported:
+// - Set Delimiter
+// - Blocks
+// - Parents
+// - Dynamic Names
+//
+// Usage:
+// \code
+//   // Creating a simple template and rendering it
+//   auto Template = Template::createTemplate("Hello, {{name}}!");
+//   Value Data = {{"name", "World"}};
+//   StringRef Rendered = Template.render(Data);
+//   // Rendered == "Hello, World!"
+//
+//   // Creating a template with a partial and rendering it
+//   auto Template = Template::createTemplate("{{>partial}}");
+//   Template.registerPartial("partial", "Hello, {{name}}!");
+//   Value Data = {{"name", "World"}};
+//   StringRef Rendered = Template.render(Data);
+//   // Rendered == "Hello, World!"
+//
+//   // Creating a template with a lambda and rendering it
+//   auto Template = Template::createTemplate("{{#lambda}}Hello,
+//                                             {{name}}!{{/lambda}}");
+//   Template.registerLambda("lambda", []() { return true; });
+//   Value Data = {{"name", "World"}};
+//   StringRef Rendered = Template.render(Data);
+//   // Rendered == "Hello, World!"
+// \endcode
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_MUSTACHE
+#define LLVM_SUPPORT_MUSTACHE
+
+#include "Error.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/Support/JSON.h"
+#include <vector>
+
+namespace llvm {
+namespace mustache {
+
+using Accessor = std::vector<SmallString<128>>;
+using Lambda = std::function<llvm::json::Value()>;
+using SectionLambda = std::function<llvm::json::Value(StringRef)>;
+
+class Token {
+public:
+  enum class Type {
+    Text,
+    Variable,
+    Partial,
+    SectionOpen,
+    SectionClose,
+    InvertSectionOpen,
+    UnescapeVariable,
+    Comment,
+  };
+
+  Token(StringRef Str);
+
+  Token(StringRef RawBody, StringRef Str, char Identifier);
+
+  StringRef getTokenBody() const { return TokenBody; };
+
+  StringRef getRawBody() const { return RawBody; };
+
+  void setTokenBody(SmallString<128> NewBody) { TokenBody = NewBody; };
+
+  Accessor getAccessor() const { return Accessor; };
+
+  Type getType() const { return TokenType; };
+
+  static Type getTokenType(char Identifier);
+
+private:
+  Type TokenType;
+  SmallString<128> RawBody;
+  Accessor Accessor;
+  SmallString<128> TokenBody;
+};
+
+class ASTNode {
+public:
+  enum Type {
+    Root,
+    Text,
+    Partial,
+    Variable,
+    UnescapeVariable,
+    Section,
+    InvertSection,
+  };
+
+  ASTNode() : T(Type::Root), LocalContext(nullptr) {};
+
+  ASTNode(StringRef Body, std::shared_ptr<ASTNode> Parent)
+      : T(Type::Text), Body(Body), Parent(Parent), LocalContext(nullptr) {};
+
+  // Constructor for Section/InvertSection/Variable/UnescapeVariable
+  ASTNode(Type T, Accessor Accessor, std::shared_ptr<ASTNode> Parent)
+      : T(T), Accessor(Accessor), Parent(Parent), LocalContext(nullptr),
+        Children({}) {};
+
+  void addChild(std::shared_ptr<ASTNode> Child) {
+    Children.emplace_back(Child);
+  };
+
+  SmallString<128> getBody() const { return Body; };
+
+  void setBody(StringRef NewBody) { Body = NewBody; };
+
+  void setRawBody(StringRef NewBody) { RawBody = NewBody; };
+
+  std::shared_ptr<ASTNode> getLastChild() const {
+    return Children.empty() ? nullptr : Children.back();
+  };
+
+  SmallString<128>
----------------
PeterChou1 wrote:

I've remove arbitrary numbers now, most of the strings are now SmallString<>

https://github.com/llvm/llvm-project/pull/105893