73 lines
1.4 KiB
C#
73 lines
1.4 KiB
C#
using System;
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using System.IO;
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using Finn.AST;
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namespace Finn;
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class ASTPrinter : IVisitor<string>
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{
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public string print(Expr expr)
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{
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return expr.accept(this);
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}
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private string parenthesize(string name, params Expr[] exprs)
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{
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var w = new StringWriter();
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w.Write($"({name}");
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foreach (Expr expr in exprs)
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{
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w.Write(" ");
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w.Write(expr.accept(this));
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}
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w.Write(")");
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return w.ToString();
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}
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public string visitBinaryExpr(Binary expr)
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{
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return parenthesize(expr.Op.lexeme, expr.Left, expr.Right);
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}
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public string visitGroupingExpr(Grouping expr)
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{
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return parenthesize("group", expr.Expression);
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}
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public string visitLiteralExpr(Literal expr)
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{
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return expr.Value.ToString() ?? "";
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}
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private string formatName(Name name)
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{
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if (name.Quoted) return $"@\"{name.Value}\"";
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return name.Value;
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}
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public string visitIdentifierExpr(Identifier expr)
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{
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return formatName(expr.Value);
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}
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public string visitUnaryExpr(Unary expr)
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{
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return parenthesize(expr.Op.lexeme, expr.Right);
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}
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public string visitIfExpr(If expr)
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{
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return parenthesize("if", expr.Condition, expr.Then, expr.Else);
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}
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public string visitSequenceExpr(Sequence expr)
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{
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return parenthesize("seq", expr.Left, expr.Right);
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}
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public string visitSelectorExpr(Selector expr)
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{
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return parenthesize(".", expr.Left, new Identifier { Value = expr.FieldName });
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}
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}
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