lumiera_/tests/library/parse-test.cpp
Ichthyostega f8517b7011 clean-up: the big anti-bang -- NullType becomes Nil
Since I've convinced myself during the last years that this kind
of typelist programming is ''not a workaround'' — it is even
superior to pattern matching on variadics for certain kinds
of tasks — the empty struct defined as `NullType` got into
more widespread use as a marker type in the Lumiera code base.

It seems adequate though to give it a much more evocative name
2025-06-02 17:46:40 +02:00

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/*
Parse(Test) - verify parsing textual specifications
Copyright (C)
2024, Hermann Vosseler <Ichthyostega@web.de>
  **Lumiera** is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version. See the file COPYING for further details.
* *****************************************************************/
/** @file parse-test.cpp
** unit test \ref Parse_test
*/
#include "lib/test/run.hpp"
#include "lib/test/test-helper.hpp"
#include "lib/meta/tuple-helper.hpp"
#include "lib/parse.hpp"
#include <vector>
namespace util {
namespace parse{
namespace test {
using lib::test::showType;
using lib::meta::typeSymbol;
using lib::meta::is_Tuple;
using std::decay_t;
using std::vector;
using std::get;
/****************************************************//**
* @test verify support for recursive descent parsing
* of structured data and specifications.
* @see parse.hpp
* @see proc-node.cpp "usage example"
*/
class Parse_test : public Test
{
virtual void
run (Arg)
{
simpleUsage();
acceptTerminal();
acceptSequential();
acceptAlternatives();
acceptIterWithDelim();
acceptOptionally();
acceptBracketed();
verify_modelBinding();
verify_recursiveSyntax();
verify_nestedSpecTerms();
}
/** @test demonstrate parsing a function-with-arguments structure. */
void
simpleUsage ()
{
using Model = std::pair<string, vector<string>>;
auto word = accept("\\w+").bindMatch();
auto term = accept(word)
.bracket (accept_repeated(",", word))
.bind([](auto res){ return Model{get<0>(res),get<1>(res)}; });
CHECK (not term.hasResult());
term.parse("great (hypertrophy, confusion, deception, profit)");
CHECK (term.success());
Model model = term.getResult();
CHECK (model.first == "great");
CHECK (model.second[0] == "hypertrophy");
CHECK (model.second[1] == "confusion" );
CHECK (model.second[2] == "deception" );
CHECK (model.second[3] == "profit" );
}
/** @test define a terminal symbol to match by parse. */
void
acceptTerminal()
{
// set up a parser function to accept some token as terminal
auto parse = Parser{"hello (\\w+) world"};
string toParse{"hello vile world of power"};
auto eval = parse (toParse);
CHECK (eval.result);
smatch res = *eval.result; // ◁——————————————————————— »result model« of a terminal parse is the RegExp-Matcher
CHECK (res.ready() and not res.empty());
CHECK (res.size() == "2"_expect );
CHECK (res.position() == "0"_expect );
CHECK (res.str() == "hello vile world"_expect );
CHECK (res[1] == "vile"_expect );
CHECK (res.suffix() == " of power"_expect );
auto syntax = Syntax{move (parse)}; // Build a syntax clause from the simple terminal symbol parser
CHECK (not syntax.hasResult());
syntax.parse (toParse);
CHECK (syntax.success()); // Syntax clause holds an implicit state from the last parse
CHECK (syntax.getResult()[1] == "vile"_expect);
// shorthand notation to start building a syntax
auto syntax2 = accept ("(\\w+) world");
CHECK (not syntax2.hasResult());
syntax2.parse (toParse);
CHECK (not syntax2.success());
string bye{"cruel world"};
syntax2.parse (bye);
CHECK (syntax2.success());
CHECK (syntax2.getResult()[1] == "cruel"_expect);
// Going full circle: extract Parser definition from syntax
auto parse2 = Parser{syntax2};
CHECK (eval.result->str(1) == "vile"); // leftover value
eval = parse2 (toParse);
CHECK (not eval.result);
eval = parse2 (bye);
CHECK (eval.result->str(1) == "cruel");
}
/** @test define a sequence of syntax structures to match by parse.
* - first demonstrate explicitly how the consecutive parsing works
* and how both models are combined into a product model (tuple)
* - demonstrate how leading whitespace is skipped automatically
* - then perform the same parse with a Syntax clause, built by
* the `seq()` builder-DSL
* - extend this Syntax by adding a further sequential clause.
*/
void
acceptSequential()
{ //_______________________________________________
// Demonstration: how sequence combinator works....
auto term1 = buildConnex ("hello");
auto term2 = buildConnex ("world");
auto parseSeq = [&](StrView toParse)
{
using R1 = decltype(term1)::Result;
using R2 = decltype(term2)::Result;
using ProductResult = std::tuple<R1,R2>;
using ProductEval = Eval<ProductResult>;
auto eval1 = term1.parse (toParse);
if (eval1.result)
{
uint end1 = eval1.consumed;
StrView restInput = toParse.substr(end1);
auto eval2 = term2.parse (restInput);
if (eval2.result)
{
uint consumedOverall = end1 + eval2.consumed;
return ProductEval{ProductResult{move(*eval1.result)
,move(*eval2.result)}
,consumedOverall
};
}
}
return ProductEval{std::nullopt};
};
string s1{"hello millions"};
string s2{"hello world"};
string s3{" hello world trade "};
auto e1 = parseSeq(s1);
CHECK (not e1.result); // Syntax 'hello'>>'world' does not accept "hello millions"
auto e2 = parseSeq(s2);
CHECK ( e2.result);
using SeqRes = decltype(e2)::Result; // Note: the result type depends on the actual syntax construction
CHECK (is_Tuple<SeqRes>()); // Result model from sequence is the tuple of terminal results
auto& [r1,r2] = *e2.result;
CHECK (r1.str() == "hello"_expect);
CHECK (r2.str() == "world"_expect);
CHECK (term2.parse(" world").result); // Note: leading whitespace skipped by the basic terminal parsers
CHECK (term2.parse("\n \t world ").result);
CHECK (not term2.parse(" old ").result);
//____________________________________________________
// DSL syntax clause builder: a sequence of terminals...
auto syntax = accept("hello").seq("world");
// Perform the same parse as demonstrated above....
CHECK (not syntax.hasResult());
syntax.parse(s1);
CHECK (not syntax.success());
syntax.parse(s2);
CHECK (syntax);
SeqRes seqModel = syntax.getResult();
CHECK (get<0>(seqModel).str() == "hello"_expect);
CHECK (get<1>(seqModel).str() == "world"_expect);
// can build extended clause from existing one
auto syntax2 = accept(syntax).seq("trade"); // Warning: seq() moves the parse function (but accept() has created a copy)
CHECK (not syntax2.hasResult());
CHECK ( syntax.hasResult()); // ...so the syntax2 is indeed an independent instance now
syntax2.parse(s2);
CHECK (not syntax2.success());
syntax2.parse(s3);
CHECK (syntax2.success());
auto seqModel2 = syntax2.getResult(); // Note: model of consecutive sequence is flattened into a single tuple
CHECK (get<0>(seqModel2).str() == "hello"_expect);
CHECK (get<1>(seqModel2).str() == "world"_expect);
CHECK (get<2>(seqModel2).str() == "trade"_expect);
}
/** @test define alternative syntax clauses to match by parse.
* - first demonstrate how a model with alternative branches can be
* populated and gradually extended while searching for a match.
* - then show explicitly the logic to check and select branches
* and construct the corresponding sum-model (variant)
* - finally demonstrate equivalent behaviour using the DSL
*/
void
acceptAlternatives()
{ //_______________________________
// Demonstrate Alt-Model mechanics
using R1 = char;
using R2 = string;
using R3 = double;
// build Model-Alternatives incrementally
using A1 = AltModel<R1>;
CHECK (showType<A1>() == "parse::AltModel<char>"_expect);
using A2 = A1::Additionally<R2>;
CHECK (showType<A2>() == "parse::AltModel<char, string>"_expect);
// create instance to represent this second branch...
A2 model2 = A2::mark_right ("seduced");
CHECK (sizeof(A2) >= sizeof(string)+sizeof(size_t));
CHECK (model2.SIZ == sizeof(string));
CHECK (model2.TOP == 1);
CHECK (model2.selected() == 1);
CHECK (model2.get<1>() == "seduced");
using A3 = A2::Additionally<R3>;
A3 model3 = A3::mark_left (move (model2));
CHECK (showType<A3>() == "parse::AltModel<char, string, double>"_expect);
CHECK (sizeof(A3) == sizeof(A2));
CHECK (model3.TOP == 2);
CHECK (model3.selected() == 1);
CHECK (model3.get<1>() == "seduced");
auto res = move(model3);
CHECK (showType<decltype(res)>() == "parse::AltModel<char, string, double>"_expect);
CHECK (sizeof(res) == sizeof(A2));
CHECK (res.selected() == 1);
CHECK (res.get<1>() == "seduced");
// AltModel with homogeneous types are special
auto hom = AltModel<int,int>::mark_right(42);
CHECK (hom.getAny() == 42);
CHECK (hom.selected() == 1 );
hom = AltModel<int,int>::mark_left(55);
CHECK (hom.getAny() == 55);
CHECK (hom.selected() == 0 );
//_____________________________________________
// Demonstration: how branch combinator works....
auto term1 = buildConnex ("brazen");
auto term2 = buildConnex ("bragging");
auto parseAlt = [&](StrView toParse)
{
using R1 = decltype(term1)::Result;
using R2 = decltype(term2)::Result;
using SumResult = AltModel<R1,R2>;
using SumEval = Eval<SumResult>;
auto eval1 = term1.parse (toParse);
if (eval1.result)
{
uint endBranch1 = eval1.consumed;
return SumEval{SumResult::mark_left (move(*eval1.result))
,endBranch1
};
}
auto eval2 = term2.parse (toParse);
if (eval2.result)
{
uint endBranch2 = eval2.consumed;
return SumEval{SumResult::mark_right (move(*eval2.result))
,endBranch2
};
}
return SumEval{std::nullopt};
};
string s1{"decent contender"};
string s2{"brazen dicktator"};
auto e1 = parseAlt(s1);
CHECK (not e1.result); // does not compute....
auto e2 = parseAlt(s2); // one hell of a match!
CHECK ( e2.result);
CHECK (e2.result->selected() == 0); // Selector-ID of the first matching branch (here #0)
CHECK (e2.result->get<0>().str() == "brazen"); // We know that branch#0 holds a RegExp-Matcher (from term1)
CHECK (e2.result->get<0>().suffix() == " dicktator");
CHECK (e2.consumed == 6);
CHECK (s2.substr(e2.consumed) == " dicktator");
//________________________________________________
// DSL parse clause builder: alternative branches...
auto syntax = accept("brazen").alt("bragging");
// Perform the same parse as demonstrated above....
CHECK (not syntax.hasResult());
syntax.parse(s1);
CHECK (not syntax.success());
syntax.parse(s2);
CHECK (syntax);
auto altModel = syntax.getResult();
CHECK (altModel.selected() == 0);
CHECK (altModel.get<0>().str() == "brazen");
// can build extended clause from existing one
auto syntax2 = accept(syntax).alt("smarmy (\\w+)");
CHECK (not syntax2.hasResult());
syntax2.parse(s1);
CHECK (not syntax2.success());
syntax2.parse(s2);
CHECK (syntax2.success());
CHECK (syntax2.getResult().N == 3); // Note: further branch has been folded into an extended AltModel
CHECK (syntax2.getResult().selected() == 0); // ... string s2 still matched the same branch (#0)
CHECK (syntax2.getResult().get<0>().str() == "brazen");
syntax2.parse("smarmy saviour");
CHECK (syntax2.success());
auto altModel2 = syntax2.getResult();
CHECK (syntax2.getResult().selected() == 2); // ... but another string can match the added branch #2
CHECK (syntax2.getResult().get<2>().str() == "smarmy saviour");
CHECK (syntax2.getResult().get<2>().str(1) == "saviour");
} // Note: syntax for this branch #2 captured an additional word
/** @test define repetitive sequence with delimiter
* - demonstrate how actually to accept such a flexible sequence
* - cover integration into the syntax clause DSL
* - repetition count and delimiter
*/
void
acceptIterWithDelim()
{ //_______________________________________________
// Demonstration: how repetitive sequence works....
auto sep = buildConnex (",");
auto word = buildConnex ("\\w+");
auto parseSeq = [&](StrView toParse)
{
using Res = decltype(word)::Result;
using IterResult = std::vector<Res>;
using IterEval = Eval<IterResult>;
uint consumed{0};
IterResult results;
auto hasResults = [&]{ return not results.empty(); };
while (true)
{
uint offset{0};
if (hasResults())
{
auto delim = sep.parse (toParse);
if (not delim.result)
break;
offset += delim.consumed;
}
auto eval = word.parse (toParse.substr(offset));
if (not eval.result)
break;
offset += eval.consumed;
results.emplace_back (move(*eval.result));
toParse = toParse.substr(offset);
consumed += offset;
}
return hasResults()? IterEval{move(results), consumed}
: IterEval{std::nullopt};
};
string s1{"seid umschlungen, Millionen"};
string s2{"beguile, extort, profit"};
auto e1 = parseSeq(s1);
CHECK (e1.result);
CHECK (e1.result->size() == 1);
CHECK (e1.result->at(0).str() == "seid");
CHECK (e1.result->at(0).suffix() == " umschlungen, Millionen");
CHECK (e1.consumed == 4);
auto e2 = parseSeq(s2);
CHECK (e2.result);
CHECK (e2.result->size() == 3);
CHECK (e2.result->at(0).str() == "beguile");
CHECK (e2.result->at(1).str() == "extort" );
CHECK (e2.result->at(2).str() == "profit" );
CHECK (e2.result->at(0).suffix() == ", extort, profit");
CHECK (e2.result->at(1).suffix() == ", profit");
CHECK (e2.result->at(2).suffix() == "" );
CHECK (e2.consumed == s2.length());
//______________________________________________
// DSL parse clause builder: iterative sequence...
auto syntax1 = accept_repeated(",", word);
// Perform the same parse as demonstrated above....
CHECK (not syntax1.hasResult());
syntax1.parse(s1);
CHECK (syntax1.success());
auto res1 = syntax1.getResult();
CHECK (res1.size() == 1);
CHECK (res1.get(0).str() == "seid");
syntax1.parse(s2);
CHECK (syntax1.success());
res1 = syntax1.getResult();
CHECK (res1.size() == 3);
CHECK (res1[0].str() == "beguile");
CHECK (res1[1].str() == "extort" );
CHECK (res1[2].str() == "profit" );
auto syntax2 = accept_repeated(1,2,",", word);
auto syntax3 = accept_repeated( 4,",", word);
syntax2.parse(s2);
syntax3.parse(s2);
CHECK ( syntax2);
CHECK (not syntax3);
CHECK (syntax2.getResult().size() == 2);
CHECK (s2.substr(syntax2.consumed()) == ", profit");
auto sx = s2 + " , \tdump";
syntax3.parse(sx);
CHECK (syntax3);
CHECK (syntax3.getResult().size() == 4);
CHECK (syntax3.getResult()[0].str() == "beguile");
CHECK (syntax3.getResult()[1].str() == "extort" );
CHECK (syntax3.getResult()[2].str() == "profit" );
CHECK (syntax3.getResult()[3].str() == "dump" );
auto syntax4 = accept_repeated(word);
syntax4.parse(s1);
CHECK (syntax4.success());
CHECK (syntax4.getResult().size() == 2);
CHECK (syntax4.getResult()[0].str() == "seid");
CHECK (syntax4.getResult()[1].str() == "umschlungen" );
CHECK (s1.substr(syntax4.consumed()) == ", Millionen");
}
/** @test define compound syntax with optional sub-clause
* - use the DSL to construct a complex syntax
* - by default, several parts are implicitly sequenced
* - here we combine repeated parts with an optional clause
* - which in turn is again a compound syntax clause
* - the produced model reflects the structure of this syntax
* - result model of the optional clause is wrapped into `std::optional`
* - terminal elements produce a `std::smatch` (RegExp matcher object)
*/
void
acceptOptionally()
{
auto syntax = accept_repeated(",", "\\w+") // first we look for comma separated words
.opt(accept("and") // then (implicitly sequenced) an optional clause
.repeat("\\w+")); // ... comprising "and" followed by several words
using Model = decay_t<decltype(syntax.getResult())>;
string s1{"fearmongering, scapegoating, intimidation"};
string s2{"charisma and divine blessing"};
CHECK (not syntax.hasResult());
syntax.parse(s1);
CHECK (syntax.success());
Model res1 = syntax.getResult();
CHECK (typeSymbol(res1) == "SeqModel");
CHECK (typeSymbol(res1.get<0>()) == "IterModel");
CHECK (typeSymbol(res1.get<1>()) == "optional");
CHECK (res1.N == 2); // 2-component tuple at top
CHECK (res1.get<0>().size() == 3); // sequence in 1st component matched 3 elements
CHECK (res1.get<0>()[0].str() == "fearmongering"); // elements in the sequence...
CHECK (res1.get<0>()[1].str() == "scapegoating");
CHECK (res1.get<0>()[2].str() == "intimidation");
CHECK (res1.get<1>() == std::nullopt); // the optional clause did not match
syntax.parse(s2);
CHECK (syntax.success());
Model res2 = syntax.getResult();
CHECK (typeSymbol(res2) == "SeqModel"); // Syntax SeqModel
CHECK (typeSymbol(res2.get<0>()) == "IterModel"); // repeat(word) opt IterModel optional
CHECK (typeSymbol(res2.get<1>()) == "optional"); // | |
CHECK (typeSymbol(*res2.get<1>()) == "SeqModel"); // Syntax SeqModel
CHECK (typeSymbol(res2.get<1>()->get<0>()) == "match_results"); // "and" repeat(word) Terminal IterModel
CHECK (typeSymbol(res2.get<1>()->get<1>()) == "IterModel"); //
CHECK (res2.get<0>().size() == 1);
CHECK (res2.get<0>()[0].str() == "charisma");
CHECK (res2.get<1>() != std::nullopt);
CHECK (res2.get<1>()->N == 2);
CHECK (res2.get<1>()->get<0>().str() == "and");
CHECK (res2.get<1>()->get<1>().size() == 2 );
CHECK (res2.get<1>()->get<1>()[0].str() == "divine" );
CHECK (res2.get<1>()->get<1>()[1].str() == "blessing" );
string s3{s1+" , "+s2};
syntax.parse(s3);
CHECK (syntax.success());
Model res3 = syntax.getResult();
CHECK (typeSymbol(res3) == "SeqModel");
CHECK (res3.get<0>().size() == 4);
CHECK (res3.get<0>()[0].str() == "fearmongering");
CHECK (res3.get<0>()[1].str() == "scapegoating");
CHECK (res3.get<0>()[2].str() == "intimidation");
CHECK (res3.get<0>()[3].str() == "charisma");
CHECK (res3.get<1>() != std::nullopt);
CHECK (res3.get<1>()->N == 2);
CHECK (res3.get<1>()->get<0>().str() == "and");
CHECK (res3.get<1>()->get<1>().size() == 2);
CHECK (res3.get<1>()->get<1>()[0].str() == "divine");
CHECK (res3.get<1>()->get<1>()[1].str() == "blessing");
}
/** @test define syntax with bracketed sub-expressions */
void
acceptBracketed()
{
string word{"\\w+"};
CHECK (not accept(word).bracket(word) .parse("so sad"));
CHECK ( accept(word).bracketOpt(word).parse("so sad"));
CHECK ( accept(word).bracketOpt(word).parse("so (sad)"));
CHECK (accept_bracket(word).parse(" ( again ) ").getResult().str() == "again");
CHECK (not accept_bracket(word) .parse("(again"));
CHECK (not accept_bracketOpt(word).parse("(again"));
CHECK ( accept_bracketOpt(word).parse("again)")); // just stops before the trailing ')'
CHECK ( accept_bracketOpt(word).parse("again)").consumed() == 5);
CHECK ( accept_bracketOpt(word).parse(" again")); // backtracks also over the whitespace
CHECK (not accept_bracket("[]",word).parse("(again)"));
CHECK (not accept_bracket("[]",word).parse("[again)"));
CHECK (not accept_bracket("[]",word).parse("(again]"));
CHECK ( accept_bracket("[]",word).parse("[again]"));
CHECK ( accept_bracket("a","n","...").parse("again")); // arbitrary expressions for open / close
CHECK (not accept_bracket("a","n","...").parse(" gain")); // opening expression "a" missing
CHECK (not accept_bracket("a","n", word).parse("again")); // "\\w+" consumes eagerly => closing expression not found
}
/** @test attach model-transformation functions at various levels,
* which is the primary intended way to build results from the parse.
*/
void
verify_modelBinding()
{
auto word{"\\w+"};
auto syntax1 = accept(word).seq(word) // get a tuple with two RegExp-Matchers
.bind([](SeqModel<smatch,smatch> res)
{
return res.get<0>().str() +"-"+ res.get<1>().str();
});
string s1{"ham actor"};
CHECK (not syntax1.hasResult());
syntax1.parse(s1);
CHECK (syntax1.success());
auto res1 = syntax1.getResult();
CHECK (showType<decltype(res1)>() == "string"); // surprise! it's a simple string (as returned from λ)
CHECK (res1 == "ham-actor"_expect);
// 💡 shortcut for RegExp match groups...
auto syntax1b = accept("(\\w+) (\\w+)");
CHECK (accept(syntax1b).bindMatch( ).parse(s1).getResult() == "ham actor"_expect );
CHECK (accept(syntax1b).bindMatch(1).parse(s1).getResult() == "ham"_expect );
CHECK (accept(syntax1b).bindMatch(2).parse(s1).getResult() == "actor"_expect );
CHECK (accept(syntax1b).bindMatch(3).parse(s1).getResult() == ""_expect );
auto wordEx = accept(word).bindMatch();
auto syntax1c = accept(wordEx)
.seq(wordEx) // sub-expressions did already transform to string
.bind([](SeqModel<string,string> res)
{ return res.get<0>() +"-"+ res.get<1>(); });
CHECK (syntax1c.parse("ham actor").getResult() == "ham-actor");
CHECK (syntax1c.parse("con artist").getResult() == "con-artist");
auto syntax1d = accept(word).seq(word)
.bindMatch(); // generic shortcut: ignore model, yield accepted part of input
CHECK (syntax1d.parse("ham actor").getResult() == "ham actor");
CHECK (syntax1d.parse(" ham actor").getResult() == "ham actor");
// another example to demonstrate arbitrary transformations:
// each sub-expr counts the letters, and the top-level binding sums those up
auto letterCnt = accept(word).bindMatch().bind([](string s){ return s.size(); });
auto syntax1e = accept(letterCnt)
.seq(letterCnt)
.bind([](auto m){ auto [l1,l2] = m; return l1+l2; });
// note this time we provide a λ-generic and use a structured binding
CHECK (syntax1e.parse("ham actor").getResult() == 8);
CHECK (syntax1e.parse("con artist").getResult() == 9);
}
/** @test definition of recursive Syntax clauses
* - pre-declared placeholder with known result
* - bind a syntax clause later to that placeholder,
* which is possibly only with a binding to yield
* the expected result type; in the example here
* we count the optional sequenced expressions
* - demonstrate textbook example of nested numeric
* expression, including parentheses and even a
* square root function. Calculate golden ratio!
*/
void
verify_recursiveSyntax()
{
auto recurse = expectResult<int>();
CHECK (not recurse.canInvoke());
recurse = accept("great")
.opt(accept("!")
.seq(recurse))
.bind([](auto m) -> int
{
auto& [_,r] = m;
return 1 + (r? get<1>(*r):0);
});
CHECK (recurse.canInvoke());
recurse.parse("great ! great ! great");
CHECK (recurse.success());
CHECK (recurse.getResult() == 3 );
CHECK (not recurse.parse(" ! great"));
CHECK (recurse.parse("great ! great actor").getResult() == 2);
CHECK (recurse.parse("great ! great ! actor").getResult() == 2);
//_____________________________________________
// Build a recursive numeric expression syntax...
auto num = accept("\\d+") .bindMatch().bind([](auto num){ return std::stod(num); });
auto sqrt = accept("").seq(num) .bind([](auto seq){ return std::sqrt(get<1>(seq)); });
CHECK (sqrt.parse(" √x ").getResult() == 0 );
CHECK (sqrt.parse(" √2 ").getResult() == "1.4142136"_expect);
// E ::= T [ + E ]
// T ::= F [ / F ]
// F ::= ( E ) | V
// V ::= num | √ num
auto expr = expectResult<double>();
auto valu = accept(num).alt(sqrt) .bind([](auto alt){ return alt.getAny(); });
auto fact = accept_bracket(expr).alt(valu) .bind([](auto alt){ return alt.getAny(); });
auto term = accept(fact).opt(accept("/") .seq(fact)) .bind([](auto seq){ auto [f1,f2] = seq; return f1 / (f2? get<1>(*f2) : 1.0); });
expr = accept(term).opt(accept("\\+").seq(expr)) .bind([](auto exp){ auto [s1,s2] = exp; return s1 + (s2? get<1>(*s2) : 0.0); });
CHECK (expr.canInvoke());
CHECK (not expr.hasResult());
expr.parse(" 42 forever");
CHECK (expr.success());
CHECK (expr.getResult() == 42 );
expr.parse(" 42 + 13 =?");
CHECK (expr.success());
CHECK (expr.getResult() == 55 );
expr.parse(" 1 + 4/3 ");
CHECK (expr.success());
CHECK (expr.getResult() == "2.3333333"_expect);
expr.parse("(2+2)/(2+1) + 4/2");
CHECK (expr.success());
CHECK (expr.getResult() == "3.3333333"_expect);
expr.parse("(1 + √5) / 2 ");
CHECK (expr.success());
CHECK (expr.getResult() == "1.618034"_expect);
}
/** @test demonstrate how to extract a nested specification term
* - accept anything not delimiter-like
* - open nested scope for parentheses and quotes
* - especially this allows proper handling of comma separated
* lists enclosed in parentheses, when the term itself is
* also part of a comma separated list — such a term-selection
* can not be achieved with regular expressions alone.
*/
void
verify_nestedSpecTerms()
{
auto content = accept(R"_([^,\\\(\)\[\]{}<>"]+)_");
auto escape = accept(R"_(\\.)_");
auto nonQuot = accept(R"_([^"\\]+)_");
auto quoted = accept_repeated(accept(nonQuot).alt(escape));
auto quote = accept_bracket("\"\"", quoted);
auto paren = expectResult<Nil>();
auto nonParen = accept(R"_([^\\\(\)"]+)_");
auto parenCont = accept_repeated(accept(nonParen)
.alt(escape)
.alt(quote)
.alt(paren));
paren = accept_bracket("()", parenCont).bind([](auto){ return Nil{}; });
auto spec = accept_repeated(accept(content)
.alt(escape)
.alt(quote)
.alt(paren));
// abbreviation for the test...
auto apply = [](auto& syntax)
{ return [&](auto const& str)
{ return accept(syntax).bindMatch()
.parse(str)
.getResult();
};
};
CHECK (apply(content)("prey .. haul .. loot") == "prey .. haul .. loot"_expect );
CHECK (apply(content)("prey .. haul ,. loot") == "prey .. haul "_expect );
CHECK (apply(content)("prey .( haul ,. loot") == "prey ."_expect );
CHECK (apply(quote)("\"prey .( haul ,\"loot") == "\"prey .( haul ,\""_expect );
CHECK (apply(quote)("\"prey \\ haul ,\"loot") == "\"prey \\ haul ,\""_expect );
CHECK (apply(quote)("\"prey\\\"haul ,\"loot") == "\"prey\\\"haul ,\""_expect );
CHECK (apply(paren)("(prey) .. haul .. loot") == "(prey)"_expect );
CHECK (apply(paren)("(prey .. haul .. loot)") == "(prey .. haul .. loot)"_expect );
CHECK (apply(paren)("(prey(..(haul)..)loot)") == "(prey(..(haul)..)loot)"_expect );
CHECK (apply(paren)("(prey \" haul)\" loot)") == "(prey \" haul)\" loot)"_expect );
CHECK (apply(paren)("(prey\\( haul)\" loot)") == "(prey\\( haul)"_expect );
CHECK (apply(spec)("\"prey .( haul ,\"loot!") == "\"prey .( haul ,\"loot!"_expect);
CHECK (apply(spec)("\"prey .( haul \",loot!") == "\"prey .( haul \""_expect );
CHECK (apply(spec)(" prey .( haul \",loot!") == "prey ."_expect );
CHECK (apply(spec)(" prey .( haul,)\"loot!") == "prey .( haul,)"_expect );
CHECK (apply(spec)(" (prey\\( haul }, loot)") == "(prey\\( haul }, loot)"_expect );
}
};
LAUNCHER (Parse_test, "unit common");
}}} // namespace util::parse::test