patterns: Added std::env and ability to pass parameters to patterns from the UI

plugins/libimhex/include/hex/helpers/utils.hpp

@@ -14,6 +14,7 @@
 #include <optional>
 #include <string>
 #include <type_traits>
+#include <variant>
 #include <vector>
 
 #include <nfd.hpp>
@@ -227,6 +228,15 @@ namespace hex {
         return iter != a.end();
     }
 
+    template<typename T, typename ... VariantTypes>
+    T get_or(const std::variant<VariantTypes...> &variant, T alt) {
+        const T *value = std::get_if<T>(&variant);
+        if (value == nullptr)
+            return alt;
+        else
+            return *value;
+    }
+
     namespace scope_guard {
 
         #define SCOPE_GUARD ::hex::scope_guard::ScopeGuardOnExit() + [&]()

plugins/libimhex/include/hex/pattern_language/evaluator.hpp

@@ -149,6 +149,18 @@ namespace hex::pl {
                 LogConsole::abortEvaluation("evaluation aborted by user");
         }
 
+        [[nodiscard]]
+        std::optional<Token::Literal> getEnvVariable(const std::string &name) const {
+            if (this->m_envVariables.contains(name))
+                return this->m_envVariables.at(name);
+            else
+                return std::nullopt;
+        }
+
+        void setEnvVariable(const std::string &name, const Token::Literal &value) {
+            this->m_envVariables[name] = value;
+        }
+
     private:
 
         void patternCreated();
@@ -173,6 +185,7 @@ namespace hex::pl {
         std::map<std::string, ContentRegistry::PatternLanguageFunctions::Function> m_customFunctions;
         std::vector<ASTNode*> m_customFunctionDefinitions;
         std::vector<Token::Literal> m_stack;
+        std::map<std::string, Token::Literal> m_envVariables;
 
         friend class PatternCreationLimiter;
     };

plugins/libimhex/include/hex/pattern_language/pattern_language.hpp

@@ -3,12 +3,14 @@
 #include <hex.hpp>
 
 #include <bit>
+#include <map>
 #include <optional>
 #include <string>
 #include <string_view>
 #include <vector>
 
 #include <hex/pattern_language/log_console.hpp>
+#include <hex/pattern_language/token.hpp>
 
 namespace hex::prv { class Provider; }
 
@@ -28,8 +30,8 @@ namespace hex::pl {
         PatternLanguage();
         ~PatternLanguage();
 
-        std::optional<std::vector<PatternData*>> executeString(prv::Provider *provider, const std::string &string);
-        std::optional<std::vector<PatternData*>> executeFile(prv::Provider *provider, const std::string &path);
+        std::optional<std::vector<PatternData*>> executeString(prv::Provider *provider, const std::string &string, const std::map<std::string, Token::Literal> &envVars = { });
+        std::optional<std::vector<PatternData*>> executeFile(prv::Provider *provider, const std::string &path, const std::map<std::string, Token::Literal> &envVars = { });
 
         void abort();