Parlot 是一个快速、轻量级和简单易用的 .NET 解析器组合器。Parlot 提供了一个基于解析器组合器的 fluent API，提供了一个更可读的语法定义。
与所有其他已知的 .NET 解析器组合器相比，Parlot 速度更快，分配更少。
Fluent API 提供了简单的分析器组合器，这些组合器可以用来表达更复杂的表达式。这个API的主要目标是提供和易于阅读的语法。另一个优点是，语法是在运行时建立的，而且可以动态地扩展。
示例（源码）：
public static readonly Parser<Expression> Expression; static FluentParser() { /* * Grammar: * expression => factor ( ( "-" | "+" ) factor )* ; * factor => unary ( ( "/" | "*" ) unary )* ; * unary => ( "-" ) unary * | primary ; * primary => NUMBER * | "(" expression ")" ; */ // The Deferred helper creates a parser that can be referenced by others before it is defined var expression = Deferred<Expression>(); var number = Terms.Decimal() .Then<Expression>(static d => new Number(d)) ; var divided = Terms.Char('/'); var times = Terms.Char('*'); var minus = Terms.Char('-'); var plus = Terms.Char('+'); var openParen = Terms.Char('('); var closeParen = Terms.Char(')'); // "(" expression ")" var groupExpression = Between(openParen, expression, closeParen); // primary => NUMBER | "(" expression ")"; var primary = number.Or(groupExpression); // The Recursive helper allows to create parsers that depend on themselves. // ( "-" ) unary | primary; var unary = Recursive<Expression>((u) => minus.And(u) .Then<Expression>(static x => new NegateExpression(x.Item2)) .Or(primary)); // factor => unary ( ( "/" | "*" ) unary )* ; var factor = unary.And(ZeroOrMany(divided.Or(times).And(unary))) .Then(static x => { // unary var result = x.Item1; // (("/" | "*") unary ) * foreach (var op in x.Item2) { result = op.Item1 switch { '/' => new Division(result, op.Item2), '*' => new Multiplication(result, op.Item2), _ => null }; } return result; }); // expression => factor ( ( "-" | "+" ) factor )* ; expression.Parser = factor.And(ZeroOrMany(plus.Or(minus).And(factor))) .Then(static x => { // factor var result = x.Item1; // (("-" | "+") factor ) * foreach (var op in x.Item2) { result = op.Item1 switch { '+' => new Addition(result, op.Item2), '-' => new Subtraction(result, op.Item2), _ => null }; } return result; }); Expression = expression; }
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