// This file is distributed under the BSD License. // See "license.txt" for details. // Copyright 2009, Jonathan Turner (jturner@minnow-lang.org) // and Jason Turner (lefticus@gmail.com) // http://www.chaiscript.com #ifndef CHAISCRIPT_EVAL_HPP_ #define CHAISCRIPT_EVAL_HPP_ #include namespace chaiscript { /** * Helper function that will set up the scope around a function call, including handling the named function parameters */ template const Boxed_Value eval_function (Eval_System &ss, TokenPtr node, const std::vector ¶m_names, const std::vector &vals) { ss.new_scope(); for (unsigned int i = 0; i < param_names.size(); ++i) { ss.add_object(param_names[i], vals[i]); } Boxed_Value retval; try { retval = eval_token(ss, node); ss.pop_scope(); } catch (const Return_Value &rv) { retval = rv.retval; ss.pop_scope(); } catch (...) { ss.pop_scope(); throw; } return retval; } /** * Evaluates the top-level file node */ template Boxed_Value eval_file(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; for (i = 0; i < node->children.size(); ++i) { retval = eval_token(ss, node->children[i]); } return retval; } /** * Evaluates a variable or function name identifier */ template Boxed_Value eval_id(Eval_System &ss, TokenPtr node) { if (node->text == "true") { return Boxed_Value(true); } else if (node->text == "false") { return Boxed_Value(false); } else { try { return ss.get_object(node->text); } catch (std::exception &) { throw Eval_Error("Can not find object: " + node->text, node); } } } /** * Evaluates a floating point number */ template Boxed_Value eval_float(Eval_System &, TokenPtr node) { return Boxed_Value(double(atof(node->text.c_str()))); } /** * Evaluates an integer */ template Boxed_Value eval_int(Eval_System &, TokenPtr node) { return Boxed_Value(atoi(node->text.c_str())); } /** * Evaluates a quoted string */ template Boxed_Value eval_quoted_string(Eval_System &, TokenPtr node) { return Boxed_Value(node->text); } /** * Evaluates a char group */ template Boxed_Value eval_single_quoted_string(Eval_System &, TokenPtr node) { if (node->text.size() == 1) { return Boxed_Value(char(node->text[0])); } else { return Boxed_Value(char((int)node->text[0] * 0xff + (int)node->text[0])); } } /** * Evaluates a string of equations in reverse order so that the right-most side has precedence */ template Boxed_Value eval_equation(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; retval = eval_token(ss, node->children.back()); if (node->children.size() > 1) { for (i = node->children.size()-3; ((int)i) >= 0; i -= 2) { if (node->children[i+1]->text == "=") { Boxed_Value lhs = eval_token(ss, node->children[i]); try { if (lhs.is_unknown()) { retval = ss.call_function("clone", Param_List_Builder() << retval); } Param_List_Builder plb; plb << lhs; plb << retval; try { retval = ss.call_function(node->children[i+1]->text, plb); } catch(const dispatch_error &){ throw Eval_Error("Mismatched types in equation", node->children[i+1]); } } catch(const dispatch_error &){ throw Eval_Error("Can not clone right hand side of equation", node->children[i+1]); } } else if (node->children[i+1]->text == ":=") { Boxed_Value lhs = eval_token(ss, node->children[i]); if (lhs.is_unknown() || type_match(lhs, retval)) { lhs.assign(retval); } else { throw Eval_Error("Mismatched types in equation", node->children[i+1]); } } else { Param_List_Builder plb; plb << eval_token(ss, node->children[i]); plb << retval; try { retval = ss.call_function(node->children[i+1]->text, plb); } catch(const dispatch_error &){ throw Eval_Error("Can not find appropriate '" + node->children[i+1]->text + "'", node->children[i+1]); } } } } return retval; } /** * Evaluates a variable declaration */ template Boxed_Value eval_var_decl(Eval_System &ss, TokenPtr node) { try { ss.add_object(node->children[0]->text, Boxed_Value()); } catch (reserved_word_error &rwe) { throw Eval_Error("Reserved word used as variable '" + node->children[0]->text + "'", node); } return ss.get_object(node->children[0]->text); } /** * Evaluates binary boolean operators. Respects short-circuiting rules. */ template Boxed_Value eval_expression(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; retval = eval_token(ss, node->children[0]); if (node->children.size() > 1) { for (i = 1; i < node->children.size(); i += 2) { bool lhs; try { lhs = boxed_cast(retval); } catch (const bad_boxed_cast &) { throw Eval_Error("Condition not boolean", node); } if (node->children[i]->text == "&&") { if (lhs) { retval = eval_token(ss, node->children[i+1]); } else { retval = Boxed_Value(false); } } else if (node->children[i]->text == "||") { if (lhs) { retval = Boxed_Value(true); } else { retval = eval_token(ss, node->children[i+1]); } } } } return retval; } /** * Evaluates comparison, additions, and multiplications and their relatives */ template Boxed_Value eval_comp_add_mul(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; retval = eval_token(ss, node->children[0]); if (node->children.size() > 1) { for (i = 1; i < node->children.size(); i += 2) { Param_List_Builder plb; plb << retval; plb << eval_token(ss, node->children[i + 1]); try { retval = ss.call_function(node->children[i]->text, plb); } catch(const dispatch_error &){ throw Eval_Error("Can not find appropriate '" + node->children[i]->text + "'", node->children[i]); } } } return retval; } /** * Evaluates an array lookup */ template Boxed_Value eval_array_call(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; retval = eval_token(ss, node->children[0]); for (i = 1; i < node->children.size(); ++i) { Param_List_Builder plb; plb << retval; plb << eval_token(ss, node->children[i]); try { retval = ss.call_function("[]", plb); } catch(std::out_of_range &) { throw Eval_Error("Out of bounds exception", node); } catch(const dispatch_error &){ throw Eval_Error("Can not find appropriate array lookup '[]' " + node->children[i]->text, node->children[i]); } } return retval; } /** * Evaluates a unary negation */ template Boxed_Value eval_negate(Eval_System &ss, TokenPtr node) { Boxed_Value retval; retval = eval_token(ss, node->children[0]); Param_List_Builder plb; plb << retval; plb << Boxed_Value(-1.0); try { return ss.call_function("*", plb); } catch(std::exception &){ throw Eval_Error("Can not find appropriate negation", node->children[0]); } } /** * Evaluates a unary boolean not */ template Boxed_Value eval_not(Eval_System &ss, TokenPtr node) { Boxed_Value retval; bool cond; try { retval = eval_token(ss, node->children[0]); cond = boxed_cast(retval); } catch (const bad_boxed_cast &) { throw Eval_Error("Boolean not('!') condition not boolean", node->children[0]); } return Boxed_Value(!cond); } /** * Evaluates any unary prefix */ template Boxed_Value eval_prefix(Eval_System &ss, TokenPtr node) { Boxed_Value retval; retval = eval_token(ss, node->children[1]); Param_List_Builder plb; plb << retval; try { return ss.call_function(node->children[0]->text, plb); } catch(std::exception &){ throw Eval_Error("Can not find appropriate prefix", node->children[0]); } } /** * Evaluates (and generates) an inline array initialization */ template Boxed_Value eval_inline_array(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; try { retval = ss.call_function("Vector", Param_List_Builder()); if (node->children.size() > 0) { for (i = 0; i < node->children[0]->children.size(); ++i) { try { Boxed_Value tmp = eval_token(ss, node->children[0]->children[i]); ss.call_function("push_back", Param_List_Builder() << retval << tmp); } catch (const dispatch_error &) { throw Eval_Error("Can not find appropriate 'push_back'", node->children[0]->children[i]); } } } } catch (const dispatch_error &) { throw Eval_Error("Can not find appropriate 'Vector()'", node); } return retval; } /** * Evaluates (and generates) an inline range initialization */ template Boxed_Value eval_inline_range(Eval_System &ss, TokenPtr node) { try { return ss.call_function("generate_range", Param_List_Builder() << eval_token(ss, node->children[0]->children[0]->children[0]) << eval_token(ss, node->children[0]->children[0]->children[1])); } catch (const dispatch_error &) { throw Eval_Error("Unable to generate range vector", node); } } /** * Evaluates (and generates) an inline map initialization */ template Boxed_Value eval_inline_map(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; try { retval = ss.call_function("Map", Param_List_Builder()); for (i = 0; i < node->children[0]->children.size(); ++i) { try { Boxed_Value key = eval_token(ss, node->children[0]->children[i]->children[0]); Boxed_Value slot = ss.call_function("[]", Param_List_Builder() << retval << key); ss.call_function("=", Param_List_Builder() << slot << eval_token(ss, node->children[0]->children[i]->children[1])); } catch (const dispatch_error &) { throw Eval_Error("Can not find appropriate '=' for map init", node->children[0]->children[i]); } } } catch (const dispatch_error &) { throw Eval_Error("Can not find appropriate 'Map()'", node); } return retval; } /** * Evaluates a function call, starting with its arguments. Handles resetting the scope to the previous one after the call. */ template Boxed_Value eval_fun_call(Eval_System &ss, TokenPtr node) { Boxed_Value retval; Param_List_Builder plb; Dispatch_Engine::Stack prev_stack = ss.get_stack(); Dispatch_Engine::Stack new_stack = ss.new_stack(); unsigned int i; if ((node->children.size() > 1) && (node->children[1]->identifier == Token_Type::Arg_List)) { for (i = 0; i < node->children[1]->children.size(); ++i) { plb << eval_token(ss, node->children[1]->children[i]); } } Boxed_Value fn; try { fn = eval_token(ss, node->children[0]); } catch(Eval_Error &ee) { ss.set_stack(prev_stack); throw Eval_Error(ee.reason, node->children[0]); } try { ss.set_stack(new_stack); retval = (*boxed_cast(fn))(plb); ss.set_stack(prev_stack); } catch(const dispatch_error &e){ ss.set_stack(prev_stack); throw Eval_Error(std::string(e.what()) + " with function '" + node->children[0]->text + "'", node->children[0]); } catch(Return_Value &rv) { ss.set_stack(prev_stack); retval = rv.retval; } catch(...) { ss.set_stack(prev_stack); throw; } return retval; } /** * Evaluates a method/attributes invocation */ template Boxed_Value eval_dot_access(Eval_System &ss, TokenPtr node) { Boxed_Value retval; std::vector > fn; Dispatch_Engine::Stack prev_stack = ss.get_stack(); Dispatch_Engine::Stack new_stack = ss.new_stack(); unsigned int i, j; //todo: Please extract a single way of doing function calls between this and eval_fun_call retval = eval_token(ss, node->children[0]); if (node->children.size() > 1) { for (i = 1; i < node->children.size(); ++i) { Param_List_Builder plb; plb << retval; if (node->children[i]->children.size() > 1) { for (j = 0; j < node->children[i]->children[1]->children.size(); ++j) { plb << eval_token(ss, node->children[i]->children[1]->children[j]); } } //std::string fun_name; Boxed_Value fn; try { if (node->children[i]->identifier == Token_Type::Fun_Call) { //fun_name = node->children[i]->children[0]->text; fn = eval_token(ss, node->children[i]->children[0]); } else { //fun_name = node->children[i]->text; fn = eval_token(ss, node->children[i]); } } catch(Eval_Error &ee) { ss.set_stack(prev_stack); throw Eval_Error(ee.reason, node->children[i]); } try { //fn = ss.get_function(fun_name); ss.set_stack(new_stack); //retval = dispatch(fn, plb); retval = (*boxed_cast(fn))(plb); ss.set_stack(prev_stack); } catch(const dispatch_error &e){ ss.set_stack(prev_stack); throw Eval_Error(std::string(e.what()), node->children[i]); } catch(Return_Value &rv) { ss.set_stack(prev_stack); retval = rv.retval; } catch(...) { ss.set_stack(prev_stack); throw; } } } return retval; } /** * Evaluates an if/elseif/else block */ template Boxed_Value eval_if(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; retval = eval_token(ss, node->children[0]); bool cond; try { cond = boxed_cast(retval); } catch (const bad_boxed_cast &) { throw Eval_Error("If condition not boolean", node->children[0]); } if (cond) { retval = eval_token(ss, node->children[1]); } else { if (node->children.size() > 2) { i = 2; while ((!cond) && (i < node->children.size())) { if (node->children[i]->text == "else") { retval = eval_token(ss, node->children[i+1]); cond = true; } else if (node->children[i]->text == "else if") { retval = eval_token(ss, node->children[i+1]); try { cond = boxed_cast(retval); } catch (const bad_boxed_cast &) { throw Eval_Error("'else if' condition not boolean", node->children[i+1]); } if (cond) { retval = eval_token(ss, node->children[i+2]); } } i = i + 3; } } } return retval; } /** * Evaluates a while block */ template Boxed_Value eval_while(Eval_System &ss, TokenPtr node) { bool cond; ss.new_scope(); try { cond = boxed_cast(eval_token(ss, node->children[0])); } catch (const bad_boxed_cast &) { ss.pop_scope(); throw Eval_Error("While condition not boolean", node->children[0]); } while (cond) { try { eval_token(ss, node->children[1]); try { cond = boxed_cast(eval_token(ss, node->children[0])); } catch (const bad_boxed_cast &) { ss.pop_scope(); throw Eval_Error("While condition not boolean", node->children[0]); } } catch (Break_Loop &) { cond = false; } } ss.pop_scope(); return Boxed_Value(); } /** * Evaluates a for block, including the for's conditions, from left to right */ template Boxed_Value eval_for(Eval_System &ss, TokenPtr node) { bool cond; ss.new_scope(); try { if (node->children.size() == 4) { eval_token(ss, node->children[0]); cond = boxed_cast(eval_token(ss, node->children[1])); } else { cond = boxed_cast(eval_token(ss, node->children[0])); } } catch (const bad_boxed_cast &) { ss.pop_scope(); throw Eval_Error("For condition not boolean", node); } while (cond) { try { if (node->children.size() == 4) { eval_token(ss, node->children[3]); eval_token(ss, node->children[2]); cond = boxed_cast(eval_token(ss, node->children[1])); } else { eval_token(ss, node->children[2]); eval_token(ss, node->children[1]); cond = boxed_cast(eval_token(ss, node->children[0])); } } catch (const bad_boxed_cast &) { ss.pop_scope(); throw Eval_Error("For condition not boolean", node); } catch (Break_Loop &) { cond = false; } } ss.pop_scope(); return Boxed_Value(); } /** * Evaluates a function definition */ template Boxed_Value eval_def(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; std::vector param_names; std::string annotation = node->annotation?node->annotation->text:""; boost::shared_ptr guard; size_t numparams = 0; std::string function_name = node->children[0]->text; TokenPtr guardnode; if ((node->children.size() > 2) && (node->children[1]->identifier == Token_Type::Arg_List)) { numparams = node->children[1]->children.size(); for (i = 0; i < numparams; ++i) { param_names.push_back(node->children[1]->children[i]->text); } if (node->children.size() > 3) { guardnode = node->children[2]; } } else { //no parameters numparams = 0; if (node->children.size() > 2) { guardnode = node->children[1]; } } if (guardnode) { guard = boost::shared_ptr (new Dynamic_Proxy_Function(boost::bind(&eval_function, boost::ref(ss), guardnode, param_names, _1), numparams)); } try { ss.add(Proxy_Function (new Dynamic_Proxy_Function(boost::bind(&eval_function, boost::ref(ss), node->children.back(), param_names, _1), numparams, annotation, guard)), function_name); } catch (reserved_word_error &rwe) { throw Eval_Error("Reserved word used as function name '" + function_name + "'", node); } return retval; } /** * Evaluates a lambda (anonymous function) */ template Boxed_Value eval_lambda(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; std::vector param_names; size_t numparams = 0; if ((node->children.size() > 0) && (node->children[0]->identifier == Token_Type::Arg_List)) { numparams = node->children[0]->children.size(); for (i = 0; i < numparams; ++i) { param_names.push_back(node->children[0]->children[i]->text); } } else { //no parameters numparams = 0; } return Boxed_Value(Proxy_Function( new Dynamic_Proxy_Function( boost::bind(&eval_function, boost::ref(ss), node->children.back(), param_names, _1), numparams))); } /** * Evaluates a scoped block. Handles resetting the scope after the block has completed. */ template Boxed_Value eval_block(Eval_System &ss, TokenPtr node) { Boxed_Value retval; unsigned int i; ss.new_scope(); for (i = 0; i < node->children.size(); ++i) { try { retval = eval_token(ss, node->children[i]); } catch (const chaiscript::Return_Value &rv) { ss.pop_scope(); retval = rv.retval; throw; } catch (...) { ss.pop_scope(); throw; } } ss.pop_scope(); return retval; } /** * Evaluates a return statement */ template Boxed_Value eval_return(Eval_System &ss, TokenPtr node) { Boxed_Value retval; if (node->children.size() > 0) { retval = eval_token(ss, node->children[0]); } else { retval = Boxed_Value(); } throw Return_Value(retval, node); } /** * Evaluates a break statement */ template Boxed_Value eval_break(Eval_System &, TokenPtr node) { throw Break_Loop(node); } /** * Top-level evaluation dispatch for all AST node types */ template Boxed_Value eval_token(Eval_System &ss, TokenPtr node) { switch (node->identifier) { case (Token_Type::File) : return eval_file(ss, node); break; case (Token_Type::Id) : return eval_id(ss, node); break; case (Token_Type::Float) : return eval_float(ss, node); break; case (Token_Type::Int) : return eval_int(ss, node); break; case (Token_Type::Quoted_String) : return eval_quoted_string(ss, node); break; case (Token_Type::Single_Quoted_String) : return eval_single_quoted_string(ss, node); break; case (Token_Type::Equation) : return eval_equation(ss, node); break; case (Token_Type::Var_Decl) : return eval_var_decl(ss, node); break; case (Token_Type::Expression) : return eval_expression(ss, node); break; case (Token_Type::Comparison) : case (Token_Type::Additive) : case (Token_Type::Multiplicative) : return eval_comp_add_mul(ss, node); break; case (Token_Type::Array_Call) : return eval_array_call(ss, node); break; case (Token_Type::Negate) : return eval_negate(ss, node); break; case (Token_Type::Not) : return eval_not(ss, node); break; case (Token_Type::Prefix) : return eval_prefix(ss, node); break; case (Token_Type::Inline_Array) : return eval_inline_array(ss, node); break; case (Token_Type::Inline_Range) : return eval_inline_range(ss, node); break; case (Token_Type::Inline_Map) : return eval_inline_map(ss, node); break; case (Token_Type::Fun_Call) : return eval_fun_call(ss, node); break; case (Token_Type::Dot_Access) : return eval_dot_access(ss, node); break; case(Token_Type::If) : return eval_if(ss, node); break; case(Token_Type::While) : return eval_while(ss, node); break; case(Token_Type::For) : return eval_for(ss, node); break; case (Token_Type::Def) : return eval_def(ss, node); break; case (Token_Type::Lambda) : return eval_lambda(ss, node); break; case (Token_Type::Block) : return eval_block(ss, node); break; case (Token_Type::Return) : return eval_return(ss, node); break; case (Token_Type::Break) : return eval_break(ss, node); break; default : return Boxed_Value(); } } } #endif /* CHAISCRIPT_EVAL_HPP_ */