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diff --git a/dev/LibCompiler/CompilerFrontend.h b/dev/LibCompiler/CompilerFrontend.h
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+/* -------------------------------------------
+
+  Copyright (C) 2024-2025 Amlal EL Mahrous, all rights reserved
+
+------------------------------------------- */
+
+#pragma once
+
+#include <LibCompiler/AssemblyInterface.h>
+
+namespace LibCompiler {
+inline auto kInvalidFrontend = "NA";
+
+/// @brief Compiler backend, implements a frontend, such as C, C++...
+/// See Toolchain, for some examples.
+class ICompilerFrontend {
+ public:
+  explicit ICompilerFrontend() = default;
+  virtual ~ICompilerFrontend() = default;
+
+  LIBCOMPILER_COPY_DEFAULT(ICompilerFrontend);
+
+  // NOTE: cast this to your user defined ast.
+  typedef void* AstType;
+
+  //! @brief Compile a syntax tree ouf of the text.
+  //! Also takes the source file name for metadata.
+
+  virtual bool Compile(std::string text, std::string file) = 0;
+
+  //! @brief What language are we dealing with?
+  virtual const char* Language() { return kInvalidFrontend; }
+
+  virtual bool IsValid() { return strcmp(this->Language(), kInvalidFrontend) > 0; }
+};
+
+struct SyntaxLeafList;
+struct SyntaxLeafList;
+struct CompilerKeyword;
+
+/// we want to do that because to separate keywords.
+enum KeywordKind {
+  kKeywordKindNamespace,
+  kKeywordKindFunctionStart,
+  kKeywordKindFunctionEnd,
+  kKeywordKindVariable,
+  kKeywordKindVariablePtr,
+  kKeywordKindType,
+  kKeywordKindTypePtr,
+  kKeywordKindExpressionBegin,
+  kKeywordKindExpressionEnd,
+  kKeywordKindArgSeparator,
+  kKeywordKindBodyStart,
+  kKeywordKindBodyEnd,
+  kKeywordKindClass,
+  kKeywordKindPtrAccess,
+  kKeywordKindAccess,
+  kKeywordKindIf,
+  kKeywordKindElse,
+  kKeywordKindElseIf,
+  kKeywordKindVariableAssign,
+  kKeywordKindVariableDec,
+  kKeywordKindVariableInc,
+  kKeywordKindConstant,
+  kKeywordKindTypedef,
+  kKeywordKindEndInstr,
+  kKeywordKindSpecifier,
+  kKeywordKindInvalid,
+  kKeywordKindReturn,
+  kKeywordKindCommentInline,
+  kKeywordKindCommentMultiLineStart,
+  kKeywordKindCommentMultiLineEnd,
+  kKeywordKindEq,
+  kKeywordKindNotEq,
+  kKeywordKindGreaterEq,
+  kKeywordKindLessEq,
+  kKeywordKindPtr,
+};
+
+/// \brief Compiler keyword information struct.
+struct CompilerKeyword {
+  std::string keyword_name;
+  KeywordKind keyword_kind = kKeywordKindInvalid;
+};
+struct SyntaxLeafList final {
+  struct SyntaxLeaf final {
+    Int32 fUserType;
+#ifdef LC_USE_STRUCTS
+    CompilerKeyword fUserData;
+#else
+    std::string fUserData;
+#endif
+
+    SyntaxLeaf() = default;
+
+    std::string        fUserValue;
+    struct SyntaxLeaf* fNext;
+  };
+
+  std::vector<SyntaxLeaf> fLeafList;
+  SizeType                fNumLeafs;
+
+  size_t                   SizeOf() { return fNumLeafs; }
+  std::vector<SyntaxLeaf>& Get() { return fLeafList; }
+  SyntaxLeaf&              At(size_t index) { return fLeafList[index]; }
+};
+
+/// find the perfect matching word in a haystack.
+/// \param haystack base string
+/// \param needle the string we search for.
+/// \return if we found it or not.
+inline bool find_word(std::string haystack, std::string needle) noexcept {
+  auto index = haystack.find(needle);
+
+  // check for needle validity.
+  if (index == std::string::npos) return false;
+
+  // declare lambda
+  auto not_part_of_word = [&](int index) {
+    if (std::isspace(haystack[index]) || std::ispunct(haystack[index])) return true;
+
+    if (index <= 0 || index >= haystack.size()) return true;
+
+    return false;
+  };
+
+  return not_part_of_word(index - 1) && not_part_of_word(index + needle.size());
+}
+
+/// find a word within strict conditions and returns a range of it.
+/// \param haystack
+/// \param needle
+/// \return position of needle.
+inline std::size_t find_word_range(std::string haystack, std::string needle) noexcept {
+  auto index = haystack.find(needle);
+
+  // check for needle validity.
+  if (index == std::string::npos) return false;
+
+  if (!isalnum((haystack[index + needle.size() + 1])) &&
+      !isdigit(haystack[index + needle.size() + 1]) &&
+      !isalnum((haystack[index - needle.size() - 1])) &&
+      !isdigit(haystack[index - needle.size() - 1])) {
+    return index;
+  }
+
+  return std::string::npos;
+}
+}  // namespace LibCompiler