832 lines
26 KiB
C#
832 lines
26 KiB
C#
using System.Diagnostics.CodeAnalysis;
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using NubLang.Common;
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using NubLang.Diagnostics;
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using NubLang.Syntax.Parsing.Node;
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using NubLang.Syntax.Tokenization;
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namespace NubLang.Syntax.Parsing;
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public sealed class Parser
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{
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private string _namespace;
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private readonly IReadOnlyList<Token> _tokens;
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private readonly List<Diagnostic> _diagnostics = [];
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private int _tokenIndex;
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public Parser(IReadOnlyList<Token> tokens)
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{
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_namespace = "default";
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_tokens = tokens;
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}
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public SyntaxTree Parse()
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{
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_diagnostics.Clear();
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_tokenIndex = 0;
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if (TryExpectSymbol(Symbol.Namespace))
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{
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_namespace = ExpectIdentifier().Value;
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}
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List<DefinitionSyntax> definitions = [];
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while (Peek().HasValue)
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{
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try
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{
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definitions.Add(ParseDefinition());
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}
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catch (ParseException ex)
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{
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_diagnostics.Add(ex.Diagnostic);
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RecoverToNextDefinition();
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}
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}
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return new SyntaxTree(_namespace, definitions, _diagnostics);
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}
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private DefinitionSyntax ParseDefinition()
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{
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var startIndex = _tokenIndex;
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var keyword = ExpectSymbol();
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var node = keyword.Symbol switch
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{
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Symbol.Extern => ParseExtern(startIndex),
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Symbol.Func => ParseFunc(startIndex),
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Symbol.Struct => ParseStruct(startIndex),
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Symbol.Trait => ParseTrait(startIndex),
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Symbol.Impl => ParseImpl(startIndex),
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_ => throw new ParseException(Diagnostic
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.Error($"Expected 'func' or 'struct', but found '{keyword.Symbol}'")
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.WithHelp("Valid definition keywords are 'func' and 'struct'")
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.At(keyword)
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.Build())
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};
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return node;
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}
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private FuncSignatureSyntax ParseFuncSignature(FuncParameterSyntax? thisArg = null)
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{
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var startIndex = _tokenIndex;
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List<FuncParameterSyntax> parameters = [];
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if (thisArg != null)
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{
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parameters.Add(thisArg);
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}
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ExpectSymbol(Symbol.OpenParen);
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while (!TryExpectSymbol(Symbol.CloseParen))
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{
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parameters.Add(ParseFuncParameter());
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if (!TryExpectSymbol(Symbol.Comma) && Peek().TryGetValue(out var token) && token is not SymbolToken { Symbol: Symbol.CloseParen })
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{
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_diagnostics.Add(Diagnostic
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.Warning("Missing comma between function parameters")
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.WithHelp("Add a ',' to separate parameters")
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.At(token)
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.Build());
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}
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}
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var returnType = TryExpectSymbol(Symbol.Colon) ? ParseType() : new NubVoidType();
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return new FuncSignatureSyntax(GetTokens(startIndex), parameters, returnType);
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}
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private FuncParameterSyntax ParseFuncParameter()
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{
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var startIndex = _tokenIndex;
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var name = ExpectIdentifier();
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ExpectSymbol(Symbol.Colon);
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var type = ParseType();
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return new FuncParameterSyntax(GetTokens(startIndex), name.Value, type);
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}
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private DefinitionSyntax ParseExtern(int startIndex)
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{
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var keyword = ExpectSymbol();
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return keyword.Symbol switch
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{
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Symbol.Func => ParseExternFunc(startIndex),
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_ => throw new ParseException(Diagnostic.Error($"Unexpected symbol {keyword.Symbol} after extern declaration").At(keyword).Build())
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};
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}
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private ExternFuncSyntax ParseExternFunc(int startIndex)
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{
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var name = ExpectIdentifier();
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var callName = name.Value;
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if (TryExpectSymbol(Symbol.Calls))
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{
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callName = ExpectIdentifier().Value;
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}
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var signature = ParseFuncSignature();
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return new ExternFuncSyntax(GetTokens(startIndex), _namespace, name.Value, callName, signature);
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}
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private LocalFuncSyntax ParseFunc(int startIndex)
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{
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var name = ExpectIdentifier();
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var signature = ParseFuncSignature();
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var body = ParseBlock();
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return new LocalFuncSyntax(GetTokens(startIndex), _namespace, name.Value, signature, body);
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}
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private StructSyntax ParseStruct(int startIndex)
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{
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var name = ExpectIdentifier().Value;
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ExpectSymbol(Symbol.OpenBrace);
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List<StructFieldSyntax> variables = [];
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var fieldIndex = 0;
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while (!TryExpectSymbol(Symbol.CloseBrace))
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{
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var fieldStartIndex = _tokenIndex;
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var variableName = ExpectIdentifier().Value;
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ExpectSymbol(Symbol.Colon);
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var variableType = ParseType();
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var variableValue = Optional<ExpressionSyntax>.Empty();
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if (TryExpectSymbol(Symbol.Assign))
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{
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variableValue = ParseExpression();
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}
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variables.Add(new StructFieldSyntax(GetTokens(fieldStartIndex), fieldIndex++, variableName, variableType, variableValue));
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}
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return new StructSyntax(GetTokens(startIndex), _namespace, name, variables);
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}
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private TraitSyntax ParseTrait(int startIndex)
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{
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var name = ExpectIdentifier().Value;
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ExpectSymbol(Symbol.OpenBrace);
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List<TraitFuncSyntax> functions = [];
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while (!TryExpectSymbol(Symbol.CloseBrace))
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{
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var funcStartIndex = _tokenIndex;
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ExpectSymbol(Symbol.Func);
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var funcName = ExpectIdentifier().Value;
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var signature = ParseFuncSignature();
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functions.Add(new TraitFuncSyntax(GetTokens(funcStartIndex), funcName, signature));
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}
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return new TraitSyntax(GetTokens(startIndex), _namespace, name, functions);
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}
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private TraitImplSyntax ParseImpl(int startIndex)
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{
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var traitType = ParseType();
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ExpectSymbol(Symbol.For);
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var forType = ParseType();
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List<TraitFuncImplSyntax> functions = [];
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ExpectSymbol(Symbol.OpenBrace);
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while (!TryExpectSymbol(Symbol.CloseBrace))
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{
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var funcStartIndex = _tokenIndex;
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ExpectSymbol(Symbol.Func);
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var functionName = ExpectIdentifier().Value;
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var signature = ParseFuncSignature(new FuncParameterSyntax([], "this", forType));
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var body = ParseBlock();
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functions.AddRange(new TraitFuncImplSyntax(GetTokens(funcStartIndex), functionName, signature, body));
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}
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return new TraitImplSyntax(GetTokens(startIndex), _namespace, traitType, forType, functions);
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}
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private StatementSyntax ParseStatement()
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{
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var startIndex = _tokenIndex;
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if (!Peek().TryGetValue(out var token))
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{
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throw new ParseException(Diagnostic
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.Error("Unexpected end of file while parsing statement")
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.At(_tokens.Last())
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.Build());
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}
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if (token is SymbolToken symbol)
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{
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switch (symbol.Symbol)
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{
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case Symbol.Return:
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return ParseReturn(startIndex);
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case Symbol.If:
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return ParseIf(startIndex);
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case Symbol.While:
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return ParseWhile(startIndex);
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case Symbol.Let:
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return ParseVariableDeclaration(startIndex);
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case Symbol.Break:
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return ParseBreak(startIndex);
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case Symbol.Continue:
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return ParseContinue(startIndex);
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}
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}
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return ParseStatementExpression(startIndex);
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}
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private StatementSyntax ParseStatementExpression(int startIndex)
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{
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var expr = ParseExpression();
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if (TryExpectSymbol(Symbol.Assign))
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{
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var value = ParseExpression();
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return new AssignmentSyntax(GetTokens(startIndex), expr, value);
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}
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return new StatementExpressionSyntax(GetTokens(startIndex), expr);
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}
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private VariableDeclarationSyntax ParseVariableDeclaration(int startIndex)
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{
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ExpectSymbol(Symbol.Let);
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var name = ExpectIdentifier().Value;
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var explicitType = Optional<NubType>.Empty();
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if (TryExpectSymbol(Symbol.Colon))
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{
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explicitType = ParseType();
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}
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var assignment = Optional<ExpressionSyntax>.Empty();
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if (TryExpectSymbol(Symbol.Assign))
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{
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assignment = ParseExpression();
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}
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return new VariableDeclarationSyntax(GetTokens(startIndex), name, explicitType, assignment);
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}
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private StatementSyntax ParseBreak(int startIndex)
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{
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ExpectSymbol(Symbol.Break);
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Next();
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return new BreakSyntax(GetTokens(startIndex));
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}
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private StatementSyntax ParseContinue(int startIndex)
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{
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ExpectSymbol(Symbol.Continue);
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return new ContinueSyntax(GetTokens(startIndex));
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}
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private ReturnSyntax ParseReturn(int startIndex)
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{
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ExpectSymbol(Symbol.Return);
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var value = Optional<ExpressionSyntax>.Empty();
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if (!TryExpectSymbol(Symbol.Semi))
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{
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value = ParseExpression();
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}
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return new ReturnSyntax(GetTokens(startIndex), value);
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}
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private IfSyntax ParseIf(int startIndex)
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{
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ExpectSymbol(Symbol.If);
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var condition = ParseExpression();
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var body = ParseBlock();
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var elseStatement = Optional<Variant<IfSyntax, BlockSyntax>>.Empty();
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if (TryExpectSymbol(Symbol.Else))
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{
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var newStartIndex = _tokenIndex;
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elseStatement = TryExpectSymbol(Symbol.If)
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? (Variant<IfSyntax, BlockSyntax>)ParseIf(newStartIndex)
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: (Variant<IfSyntax, BlockSyntax>)ParseBlock();
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}
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return new IfSyntax(GetTokens(startIndex), condition, body, elseStatement);
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}
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private WhileSyntax ParseWhile(int startIndex)
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{
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ExpectSymbol(Symbol.While);
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var condition = ParseExpression();
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var body = ParseBlock();
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return new WhileSyntax(GetTokens(startIndex), condition, body);
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}
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private ExpressionSyntax ParseExpression(int precedence = 0)
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{
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var startIndex = _tokenIndex;
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var left = ParsePrimaryExpression();
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while (true)
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{
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var token = Peek();
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if (!token.HasValue || token.Value is not SymbolToken symbolToken || !TryGetBinaryOperator(symbolToken.Symbol, out var op) ||
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GetBinaryOperatorPrecedence(op.Value) < precedence)
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{
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break;
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}
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Next();
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var right = ParseExpression(GetBinaryOperatorPrecedence(op.Value) + 1);
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left = new BinaryExpressionSyntax(GetTokens(startIndex), left, op.Value, right);
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}
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return left;
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}
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private int GetBinaryOperatorPrecedence(BinaryOperator @operator)
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{
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return @operator switch
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{
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BinaryOperator.Multiply => 3,
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BinaryOperator.Divide => 3,
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BinaryOperator.Plus => 2,
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BinaryOperator.Minus => 2,
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BinaryOperator.GreaterThan => 1,
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BinaryOperator.GreaterThanOrEqual => 1,
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BinaryOperator.LessThan => 1,
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BinaryOperator.LessThanOrEqual => 1,
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BinaryOperator.Equal => 0,
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BinaryOperator.NotEqual => 0,
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_ => throw new ArgumentOutOfRangeException(nameof(@operator), @operator, null)
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};
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}
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private bool TryGetBinaryOperator(Symbol symbol, [NotNullWhen(true)] out BinaryOperator? binaryExpressionOperator)
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{
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switch (symbol)
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{
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case Symbol.Equal:
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binaryExpressionOperator = BinaryOperator.Equal;
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return true;
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case Symbol.NotEqual:
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binaryExpressionOperator = BinaryOperator.NotEqual;
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return true;
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case Symbol.LessThan:
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binaryExpressionOperator = BinaryOperator.LessThan;
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return true;
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case Symbol.LessThanOrEqual:
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binaryExpressionOperator = BinaryOperator.LessThanOrEqual;
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return true;
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case Symbol.GreaterThan:
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binaryExpressionOperator = BinaryOperator.GreaterThan;
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return true;
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case Symbol.GreaterThanOrEqual:
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binaryExpressionOperator = BinaryOperator.GreaterThanOrEqual;
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return true;
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case Symbol.Plus:
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binaryExpressionOperator = BinaryOperator.Plus;
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return true;
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case Symbol.Minus:
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binaryExpressionOperator = BinaryOperator.Minus;
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return true;
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case Symbol.Star:
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binaryExpressionOperator = BinaryOperator.Multiply;
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return true;
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case Symbol.ForwardSlash:
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binaryExpressionOperator = BinaryOperator.Divide;
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return true;
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default:
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binaryExpressionOperator = null;
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return false;
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}
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}
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private ExpressionSyntax ParsePrimaryExpression()
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{
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var startIndex = _tokenIndex;
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ExpressionSyntax expr;
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var token = ExpectToken();
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switch (token)
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{
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case LiteralToken literal:
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{
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expr = new LiteralSyntax(GetTokens(startIndex), literal.Value, literal.Kind);
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break;
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}
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case IdentifierToken identifier:
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{
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var @namespace = Optional<string>.Empty();
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var name = identifier.Value;
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if (TryExpectSymbol(Symbol.DoubleColon))
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{
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@namespace = identifier.Value;
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name = ExpectIdentifier().Value;
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}
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expr = new IdentifierSyntax(GetTokens(startIndex), @namespace, name);
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break;
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}
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case SymbolToken symbolToken:
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{
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switch (symbolToken.Symbol)
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{
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case Symbol.Func:
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{
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List<AnonymousFuncParameterSyntax> parameters = [];
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ExpectSymbol(Symbol.OpenParen);
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while (!TryExpectSymbol(Symbol.CloseParen))
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{
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var parameterStartIndex = _tokenIndex;
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var name = ExpectIdentifier();
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parameters.Add(new AnonymousFuncParameterSyntax(GetTokens(parameterStartIndex), name.Value));
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}
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var body = ParseBlock();
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expr = new AnonymousFuncSyntax(GetTokens(startIndex), parameters, body);
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break;
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}
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case Symbol.OpenParen:
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{
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var expression = ParseExpression();
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ExpectSymbol(Symbol.CloseParen);
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expr = expression;
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break;
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}
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case Symbol.Minus:
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{
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var expression = ParsePrimaryExpression();
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expr = new UnaryExpressionSyntax(GetTokens(startIndex), UnaryOperator.Negate, expression);
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break;
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}
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case Symbol.Bang:
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{
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var expression = ParsePrimaryExpression();
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expr = new UnaryExpressionSyntax(GetTokens(startIndex), UnaryOperator.Invert, expression);
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break;
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}
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case Symbol.OpenBracket:
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{
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var capacity = ParseExpression();
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ExpectSymbol(Symbol.CloseBracket);
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var type = ParseType();
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expr = new ArrayInitializerSyntax(GetTokens(startIndex), capacity, type);
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break;
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}
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case Symbol.Alloc:
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{
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var type = ParseType();
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Dictionary<string, ExpressionSyntax> initializers = [];
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ExpectSymbol(Symbol.OpenBrace);
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while (!TryExpectSymbol(Symbol.CloseBrace))
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{
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var name = ExpectIdentifier().Value;
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ExpectSymbol(Symbol.Assign);
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var value = ParseExpression();
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initializers.Add(name, value);
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}
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expr = new StructInitializerSyntax(GetTokens(startIndex), type, initializers);
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break;
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}
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default:
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{
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throw new ParseException(Diagnostic
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.Error($"Unexpected symbol '{symbolToken.Symbol}' in expression")
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.WithHelp("Expected literal, identifier, or '(' to start expression")
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.At(symbolToken)
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.Build());
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}
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}
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break;
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}
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default:
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{
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throw new ParseException(Diagnostic
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.Error($"Unexpected token '{token.GetType().Name}' in expression")
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.WithHelp("Expected literal, identifier, or parenthesized expression")
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.At(token)
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.Build());
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}
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}
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return ParsePostfixOperators(startIndex, expr);
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}
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private ExpressionSyntax ParsePostfixOperators(int startIndex, ExpressionSyntax expr)
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{
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while (true)
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{
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if (TryExpectSymbol(Symbol.Ampersand))
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{
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expr = new AddressOfSyntax(GetTokens(startIndex), expr);
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break;
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}
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if (TryExpectSymbol(Symbol.Caret))
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{
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expr = new DereferenceSyntax(GetTokens(startIndex), expr);
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continue;
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}
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if (TryExpectSymbol(Symbol.Period))
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{
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var structMember = ExpectIdentifier().Value;
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expr = new MemberAccessSyntax(GetTokens(startIndex), expr, structMember);
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continue;
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}
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if (TryExpectSymbol(Symbol.OpenBracket))
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{
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var index = ParseExpression();
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ExpectSymbol(Symbol.CloseBracket);
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expr = new ArrayIndexAccessSyntax(GetTokens(startIndex), expr, index);
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continue;
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}
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if (TryExpectSymbol(Symbol.OpenParen))
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{
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var parameters = new List<ExpressionSyntax>();
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while (!TryExpectSymbol(Symbol.CloseParen))
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{
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parameters.Add(ParseExpression());
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if (!TryExpectSymbol(Symbol.Comma) && Peek().TryGetValue(out var nextToken) && nextToken is not SymbolToken { Symbol: Symbol.CloseParen })
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{
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_diagnostics.Add(Diagnostic
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.Warning("Missing comma between function arguments")
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.WithHelp("Add a ',' to separate arguments")
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.At(nextToken)
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.Build());
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}
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}
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expr = new FuncCallSyntax(GetTokens(startIndex), expr, parameters);
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continue;
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}
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break;
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}
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return expr;
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}
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private BlockSyntax ParseBlock()
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{
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var startIndex = _tokenIndex;
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ExpectSymbol(Symbol.OpenBrace);
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List<StatementSyntax> statements = [];
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while (Peek().HasValue && !TryExpectSymbol(Symbol.CloseBrace))
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{
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try
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{
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statements.Add(ParseStatement());
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}
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catch (ParseException ex)
|
|
{
|
|
_diagnostics.Add(ex.Diagnostic);
|
|
Next();
|
|
}
|
|
}
|
|
|
|
return new BlockSyntax(GetTokens(startIndex), statements);
|
|
}
|
|
|
|
private NubType ParseType()
|
|
{
|
|
if (TryExpectIdentifier(out var name))
|
|
{
|
|
return name.Value switch
|
|
{
|
|
"void" => new NubVoidType(),
|
|
"string" => new NubStringType(),
|
|
"cstring" => new NubCStringType(),
|
|
"i64" => new NubPrimitiveType(PrimitiveTypeKind.I64),
|
|
"i32" => new NubPrimitiveType(PrimitiveTypeKind.I32),
|
|
"i16" => new NubPrimitiveType(PrimitiveTypeKind.I16),
|
|
"i8" => new NubPrimitiveType(PrimitiveTypeKind.I8),
|
|
"u64" => new NubPrimitiveType(PrimitiveTypeKind.U64),
|
|
"u32" => new NubPrimitiveType(PrimitiveTypeKind.U32),
|
|
"u16" => new NubPrimitiveType(PrimitiveTypeKind.U16),
|
|
"u8" => new NubPrimitiveType(PrimitiveTypeKind.U8),
|
|
"f64" => new NubPrimitiveType(PrimitiveTypeKind.F64),
|
|
"f32" => new NubPrimitiveType(PrimitiveTypeKind.F32),
|
|
"bool" => new NubPrimitiveType(PrimitiveTypeKind.Bool),
|
|
_ => ParseCustomType()
|
|
};
|
|
|
|
NubCustomType ParseCustomType()
|
|
{
|
|
var @namespace = _namespace;
|
|
if (TryExpectSymbol(Symbol.DoubleColon))
|
|
{
|
|
@namespace = ExpectIdentifier().Value;
|
|
}
|
|
|
|
return new NubCustomType(@namespace, name.Value);
|
|
}
|
|
}
|
|
|
|
if (TryExpectSymbol(Symbol.Caret))
|
|
{
|
|
var baseType = ParseType();
|
|
return new NubPointerType(baseType);
|
|
}
|
|
|
|
if (TryExpectSymbol(Symbol.Func))
|
|
{
|
|
ExpectSymbol(Symbol.OpenParen);
|
|
List<NubType> parameters = [];
|
|
while (!TryExpectSymbol(Symbol.CloseParen))
|
|
{
|
|
var parameter = ParseType();
|
|
parameters.Add(parameter);
|
|
if (!TryExpectSymbol(Symbol.Comma) && Peek().TryGetValue(out var nextToken) && nextToken is not SymbolToken { Symbol: Symbol.CloseParen })
|
|
{
|
|
_diagnostics.Add(Diagnostic
|
|
.Warning("Missing comma between func type arguments")
|
|
.WithHelp("Add a ',' to separate arguments")
|
|
.At(nextToken)
|
|
.Build());
|
|
}
|
|
}
|
|
|
|
var returnType = TryExpectSymbol(Symbol.Colon) ? ParseType() : new NubVoidType();
|
|
|
|
return new NubFuncType(returnType, parameters);
|
|
}
|
|
|
|
if (TryExpectSymbol(Symbol.OpenBracket))
|
|
{
|
|
ExpectSymbol(Symbol.CloseBracket);
|
|
var baseType = ParseType();
|
|
return new NubArrayType(baseType);
|
|
}
|
|
|
|
if (!Peek().TryGetValue(out var peekToken))
|
|
{
|
|
throw new ParseException(Diagnostic
|
|
.Error("Unexpected end of file while parsing type")
|
|
.WithHelp("Expected a type name")
|
|
.At(_tokens.Last())
|
|
.Build());
|
|
}
|
|
|
|
throw new ParseException(Diagnostic
|
|
.Error("Invalid type Syntax")
|
|
.WithHelp("Expected type name, '^' for pointer, or '[]' for array")
|
|
.At(peekToken)
|
|
.Build());
|
|
}
|
|
|
|
private Token ExpectToken()
|
|
{
|
|
if (!Peek().TryGetValue(out var token))
|
|
{
|
|
throw new ParseException(Diagnostic
|
|
.Error("Unexpected end of file")
|
|
.WithHelp("Expected more tokens to complete the Syntax")
|
|
.At(_tokens.Last())
|
|
.Build());
|
|
}
|
|
|
|
Next();
|
|
return token;
|
|
}
|
|
|
|
private SymbolToken ExpectSymbol()
|
|
{
|
|
var token = ExpectToken();
|
|
if (token is not SymbolToken symbol)
|
|
{
|
|
throw new ParseException(Diagnostic
|
|
.Error($"Expected symbol, but found {token.GetType().Name}")
|
|
.WithHelp("This position requires a symbol like '(', ')', '{', '}', etc.")
|
|
.At(token)
|
|
.Build());
|
|
}
|
|
|
|
return symbol;
|
|
}
|
|
|
|
private void ExpectSymbol(Symbol expectedSymbol)
|
|
{
|
|
var token = ExpectSymbol();
|
|
if (token.Symbol != expectedSymbol)
|
|
{
|
|
throw new ParseException(Diagnostic
|
|
.Error($"Expected '{expectedSymbol}', but found '{token.Symbol}'")
|
|
.WithHelp($"Insert '{expectedSymbol}' here")
|
|
.At(token)
|
|
.Build());
|
|
}
|
|
}
|
|
|
|
private bool TryExpectSymbol(Symbol symbol)
|
|
{
|
|
if (Peek() is { Value: SymbolToken symbolToken } && symbolToken.Symbol == symbol)
|
|
{
|
|
Next();
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
private bool TryExpectIdentifier([NotNullWhen(true)] out IdentifierToken? identifier)
|
|
{
|
|
if (Peek() is { Value: IdentifierToken identifierToken })
|
|
{
|
|
identifier = identifierToken;
|
|
Next();
|
|
return true;
|
|
}
|
|
|
|
identifier = null;
|
|
return false;
|
|
}
|
|
|
|
private IdentifierToken ExpectIdentifier()
|
|
{
|
|
var token = ExpectToken();
|
|
if (token is not IdentifierToken identifier)
|
|
{
|
|
throw new ParseException(Diagnostic
|
|
.Error($"Expected identifier, but found {token.GetType().Name}")
|
|
.WithHelp("Provide a valid identifier name here")
|
|
.At(token)
|
|
.Build());
|
|
}
|
|
|
|
return identifier;
|
|
}
|
|
|
|
private void RecoverToNextDefinition()
|
|
{
|
|
while (Peek().HasValue)
|
|
{
|
|
var token = Peek().Value;
|
|
if (token is SymbolToken { Symbol: Symbol.Extern or Symbol.Func or Symbol.Struct or Symbol.Trait or Symbol.Impl })
|
|
{
|
|
break;
|
|
}
|
|
|
|
Next();
|
|
}
|
|
}
|
|
|
|
private Optional<Token> Peek(int offset = 0)
|
|
{
|
|
var peekIndex = _tokenIndex + offset;
|
|
if (peekIndex < _tokens.Count())
|
|
{
|
|
return _tokens.ElementAt(peekIndex);
|
|
}
|
|
|
|
return Optional<Token>.Empty();
|
|
}
|
|
|
|
private void Next()
|
|
{
|
|
_tokenIndex++;
|
|
}
|
|
|
|
private List<Token> GetTokens(int startIndex)
|
|
{
|
|
return _tokens.Skip(startIndex).Take(Math.Min(_tokenIndex, _tokens.Count() - 1) - startIndex).ToList();
|
|
}
|
|
}
|
|
|
|
public class ParseException : Exception
|
|
{
|
|
public Diagnostic Diagnostic { get; }
|
|
|
|
public ParseException(Diagnostic diagnostic) : base(diagnostic.Message)
|
|
{
|
|
Diagnostic = diagnostic;
|
|
}
|
|
} |