Ichthyostega
4f676f7213
So this turned out to be much more challenging than expected, due to the fact that, with this design, typing information is only available at compile-time. The key trick was to use a ''double-dispatch'' based on a generic lambda. In the end, this could be rounded out to be self-contained library helper, which is even fully copyable and assignable and properly invokes all payload constructors and destructors. The flip side is that such a design is obviously very flexible and direct regarding the parser model-bindings, and it should be fairly well optimisable, since the structure is entirely static and without any virtual dispatch. Proper handling of payload lifecycle was verified using a tracking test object with checksum.
279 lines
9.8 KiB
C++
279 lines
9.8 KiB
C++
/*
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Parse(Test) - verify parsing textual specifications
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Copyright (C)
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2024, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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* *****************************************************************/
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/** @file parse-test.cpp
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** unit test \ref Parse_test
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*/
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#include "lib/test/run.hpp"
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#include "lib/test/test-helper.hpp"
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#include "lib/parse.hpp"
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//#include "lib/iter-explorer.hpp"
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//#include "lib/format-util.hpp"
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#include "lib/meta/tuple-helper.hpp"
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#include "lib/test/diagnostic-output.hpp"//////////////////TODO
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//#include "lib/util.hpp"
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//#include <vector>
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//#include <memory>
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namespace util {
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namespace parse{
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namespace test {
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using lib::test::showType;
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using lib::meta::is_Tuple;
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using std::get;
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// using util::join;
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// using util::isnil;
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// using std::vector;
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// using std::shared_ptr;
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// using std::make_shared;
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// using LERR_(ITER_EXHAUST);
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// using LERR_(INDEX_BOUNDS);
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namespace { // test fixture
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// const uint NUM_ELMS = 10;
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// using Numz = vector<uint>;
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} // (END)fixture
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/************************************************************************//**
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* @test verify helpers and shortcuts for simple recursive descent parsing
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* of structured data and specifications.
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*
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* @see parse.hpp
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* @see proc-node.cpp "usage example"
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*/
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class Parse_test : public Test
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{
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virtual void
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run (Arg)
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{
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simpleBlah();
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acceptTerminal();
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acceptSequential();
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acceptAlternatives();
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}
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/** @test TODO just blah. */
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void
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simpleBlah ()
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{
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}
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/** @test define a terminal symbol to match by parse. */
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void
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acceptTerminal()
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{
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// set up a parser function to accept some token as terminal
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auto parse = Parser{"hello (\\w+) world"};
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string toParse{"hello vile world of power"};
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auto eval = parse (toParse);
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CHECK (eval.result);
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auto res = *eval.result; // ◁——————————— the »result model« of a terminal parse is the RegExp-Matcher
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CHECK (res.ready() and not res.empty());
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CHECK (res.size() == "2"_expect );
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CHECK (res.position() == "0"_expect );
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CHECK (res.str() == "hello vile world"_expect );
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CHECK (res[1] == "vile"_expect );
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CHECK (res.suffix() == " of power"_expect );
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auto syntax = Syntax{move (parse)}; // Build a syntax clause from the simple terminal symbol parser
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CHECK (not syntax.hasResult());
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syntax.parse (toParse);
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CHECK (syntax.success()); // Syntax clause holds an implicit state from the last parse
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CHECK (syntax.getResult()[1] == "vile"_expect);
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// shorthand notation to start building a syntax
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auto syntax2 = accept ("(\\w+) world");
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CHECK (not syntax2.hasResult());
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syntax2.parse (toParse);
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CHECK (not syntax2.success());
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string bye{"cruel world"};
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syntax2.parse (bye);
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CHECK (syntax2.success());
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CHECK (syntax2.getResult()[1] == "cruel"_expect);
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// going full circle: extract parser def from syntax
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// using Conn = decltype(syntax2)::Connex;
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// Conn conny{syntax2};
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// auto parse2 = Parser{conny};
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auto parse2 = Parser{syntax2.getConny()};
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CHECK (eval.result->str(1) == "vile");
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eval = parse2 (toParse);
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CHECK (not eval.result);
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eval = parse2 (bye);
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CHECK (eval.result->str(1) == "cruel");
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}
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/** @test define a sequence of syntax structures to match by parse. */
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void
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acceptSequential()
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{
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// Demonstration: how sequence combinator works....
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auto term1 = buildConnex ("hello");
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auto term2 = buildConnex ("world");
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auto parseSeq = [&](StrView toParse)
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{
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using R1 = decltype(term1)::Result;
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using R2 = decltype(term2)::Result;
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using ProductResult = std::tuple<R1,R2>;
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using ProductEval = Eval<ProductResult>;
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auto eval1 = term1.parse (toParse);
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if (eval1.result)
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{
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uint end1 = eval1.consumed;
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StrView restInput = toParse.substr(end1);
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auto eval2 = term2.parse (restInput);
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if (eval2.result)
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{
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uint consumedOverall = end1 + eval2.consumed;
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return ProductEval{ProductResult{move(*eval1.result)
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,move(*eval2.result)}
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,consumedOverall
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};
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}
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}
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return ProductEval{std::nullopt};
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};
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string s1{"hello millions"};
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string s2{"hello world"};
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string s3{" hello world trade "};
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auto e1 = parseSeq(s1);
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CHECK (not e1.result); // Syntax 'hello'>>'world' does not accept "hello millions"
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auto e2 = parseSeq(s2);
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CHECK ( e2.result);
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using SeqRes = std::decay_t<decltype(*e2.result)>; // Note: the result type depends on the actual syntax construction
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CHECK (is_Tuple<SeqRes>()); // Result model from sequence is the tuple of terminal results
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auto& [r1,r2] = *e2.result;
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CHECK (r1.str() == "hello"_expect);
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CHECK (r2.str() == "world"_expect);
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CHECK (term2.parse(" world").result); // Note: leading whitespace skipped by the basic terminal parsers
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CHECK (term2.parse("\n \t world ").result);
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CHECK (not term2.parse(" old ").result);
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// DSL parse clause builder: a sequence of terminals...
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auto syntax = accept("hello").seq("world");
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// Perform the same parse as demonstrated above....
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CHECK (not syntax.hasResult());
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syntax.parse(s1);
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CHECK (not syntax.success());
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syntax.parse(s2);
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CHECK (syntax);
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SeqRes seqModel = syntax.getResult();
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CHECK (get<0>(seqModel).str() == "hello"_expect);
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CHECK (get<1>(seqModel).str() == "world"_expect);
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// can build extended clause from existing one
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auto syntax2 = syntax.seq("trade");
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CHECK (not syntax2.hasResult());
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syntax2.parse(s2);
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CHECK (not syntax2.success());
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syntax2.parse(s3);
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CHECK (syntax2.success());
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auto seqModel2 = syntax2.getResult(); // Note: model of consecutive sequence is flattened into a single tuple
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CHECK (get<0>(seqModel2).str() == "hello"_expect);
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CHECK (get<1>(seqModel2).str() == "world"_expect);
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CHECK (get<2>(seqModel2).str() == "trade"_expect);
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}
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/** @test TODO WIP define alternative syntax structures to match by parse.
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* - first demonstrate how a model with alternative branches can be
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* populated and gradually extended while searching for a match.
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*/
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void
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acceptAlternatives()
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{
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using R1 = char;
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using R2 = string;
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using R3 = double;
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using A1 = AltModel<R1>;
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SHOW_EXPR(showType<A1>())
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CHECK (showType<A1>() == "parse::AltModel<char>"_expect);
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string s{"second"};
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using A2 = A1::Additionally<R2>;
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SHOW_EXPR(showType<A2>())
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CHECK (showType<A2>() == "parse::AltModel<char, string>"_expect);
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A2 model2{s};
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SHOW_EXPR(sizeof(A2));
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CHECK (sizeof(A2) >= sizeof(string)+sizeof(size_t));
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SHOW_EXPR(model2.SIZ);
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CHECK (model2.SIZ == sizeof(string));
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SHOW_EXPR(model2.TOP);
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CHECK (model2.TOP == 1);
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SHOW_EXPR(model2.selected())
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CHECK (model2.selected() == 1);
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SHOW_EXPR(model2.get<1>())
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CHECK (model2.get<1>() == "second");
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using A3 = A2::Additionally<R3>;
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A3 model3{model2.addBranch<R3>()};
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SHOW_TYPE(A3)
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SHOW_EXPR(showType<A3>())
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CHECK (showType<A3>() == "parse::AltModel<char, string, double>"_expect);
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SHOW_EXPR(sizeof(A3));
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CHECK (sizeof(A3) == sizeof(A2));
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SHOW_EXPR(model3.SIZ);
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SHOW_EXPR(model3.TOP);
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CHECK (model3.TOP == 2);
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SHOW_EXPR(model3.selected())
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CHECK (model3.selected() == 1);
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SHOW_EXPR(model3.get<1>())
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CHECK (model3.get<1>() == "second");
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auto res = move(model3);
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SHOW_TYPE(decltype(res))
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SHOW_EXPR(showType<decltype(res)>())
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CHECK (showType<decltype(res)>() == "parse::AltModel<char, string, double>"_expect);
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SHOW_EXPR(sizeof(res))
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CHECK (sizeof(res) == sizeof(A2));
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SHOW_EXPR(res.selected())
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CHECK (res.selected() == 1);
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SHOW_EXPR(res.get<1>())
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CHECK (res.get<1>() == "second");
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}
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};
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LAUNCHER (Parse_test, "unit common");
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}}} // namespace util::parse::test
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