public TrlParser()
{
_pegFacade = new PegFacade <TokenNames, ParseRuleNames, ITrlParseResult>();
CreateTokenizer();
CreateSemanticActions();
CreateParser();
}
private static Tokenizer <Tokens> GetTokenizer(PegFacade <Tokens, RuleNames, double?> peg)
{
return(peg.Tokenizer(new[] {
peg.Token(Tokens.Plus, new Regex(@"\+")),
peg.Token(Tokens.Number, new Regex(@"[-+]?[0-9]+\.?[0-9]*")),
peg.Token(Tokens.Whitespace, new Regex(@"\s+"))
}));
}
private static Parser <Tokens, RuleNames, double?> DefineParser(PegFacade <Tokens, RuleNames, double?> peg)
{
var grammer = @"Add => (Add [Plus] Add) | [Number]";
var rules = peg.ParserGenerator.GetParsingRules(grammer);
var parser = peg.Parser(RuleNames.Add, rules); // RuleNames.Add is the start symbol
return(parser);
}
public Generator(PegFacade <TTokenTypeName, TNonTerminalName, TActionResult> outputPeg)
{
_inputPeg = new PegFacade <TokenNames, RuleName, IParserGeneratorResult>();
_outputPeg = outputPeg;
BuildTokenizer();
BuildSemantics();
BuildParser();
}
private static void DefineSemanticActions(PegFacade <Tokens, RuleNames, double?> peg)
{
var semanticActions = peg.DefaultSemanticActions;
semanticActions.OrderedChoiceAction = (matchedTokens, subresults, matchedPeg) => subresults.First();
semanticActions.SetTerminalAction(Tokens.Number,
(matchedTokens, subresults, matchedPeg) => double.Parse(matchedTokens.GetMatchedString()));
semanticActions.SetNonTerminalAction(RuleNames.Add,
(matchedTokens, subresults, matchedPeg) => subresults.First());
semanticActions.SequenceAction = (matchedTokens, subresults, matchedPeg) =>
{
// "+" will return a sub result of null because if does not have an
// action associated with the Plus token via a SetTerminalAction call
return(subresults.Where(s => s.HasValue).Sum(s => s.Value));
};
}
static void Main(string[] args)
{
var peg = new PegFacade <Tokens, RuleNames, double?>();
const string input = "1 + 2 + 3";
// Define tokenizer
Tokenizer <Tokens> tokenizer = GetTokenizer(peg);
// Define semantic callback functions
DefineSemanticActions(peg);
// Define PEG rules
Parser <Tokens, RuleNames, double?> parser = DefineParser(peg);
// Tokenize input
var tokenResult = tokenizer.Tokenize(input);
if (!tokenResult.Succeed)
{
Console.WriteLine("Invalid input");
return;
}
// Remove whitespace
var inputNoWhitespace = tokenResult.MatchedRanges
.Where(t => t.TokenName != Tokens.Whitespace)
.ToList().AsReadOnly();
// Parse
var output = parser.Parse(inputNoWhitespace);
if (!output.Succeed)
{
Console.WriteLine("Invalid input");
}
else
{
Console.WriteLine("Parse succeeded");
Console.WriteLine($"Sum = {output.SemanticActionResult}");
}
}
public SemanticActionsTests()
{
_peg = new PegFacade <TokenNames, ParsingRuleNames, IAstResult>();
}
public ParserGeneratorTests()
{
_peg = new PegFacade <TokenNames, ParsingRuleNames, string>();
}