Pass around an immutable scope stack in resolver
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d5ffd1e414
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160
Resolver.cs
160
Resolver.cs
@ -1,12 +1,11 @@
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using System;
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using System.Collections.Generic;
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using System.Collections.Immutable;
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using Finn;
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using Finn.AST;
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class Resolver : IExprVisitor<ValueTuple, ValueTuple>
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class Resolver : IExprVisitor<ImmutableStack<ImmutableHashSet<string>>, ValueTuple>
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{
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private class NameCollection
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{
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@ -72,78 +71,66 @@ class Resolver : IExprVisitor<ValueTuple, ValueTuple>
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}
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}
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private static readonly ValueTuple Void = ValueTuple.Create();
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private readonly Interpreter Interpreter;
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private readonly Stack<IReadOnlySet<string>> scopes = new();
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Resolver(Interpreter interpreter)
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{
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Interpreter = interpreter;
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}
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private void Resolve(ValueTuple context, Expr expr)
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private void Resolve(ImmutableStack<ImmutableHashSet<string>> scopes, Expr expr)
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{
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expr.accept(context, this);
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expr.accept(scopes, this);
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}
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private void ResolveInNewScope(ValueTuple context, IReadOnlySet<string> vars, Expr expr)
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private void Resolve(ImmutableStack<ImmutableHashSet<string>> scopes, ImmutableHashSet<string> newScope, Expr value)
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{
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BeginScope(vars);
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Resolve(context, expr);
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EndScope();
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Resolve(scopes.Push(newScope), value);
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}
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private void BeginScope(IReadOnlySet<string> vars)
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public ValueTuple visitBinaryExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Binary expr)
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{
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scopes.Push(vars);
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Resolve(scopes, expr.Left);
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Resolve(scopes, expr.Right);
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return Void;
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}
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private void EndScope()
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public ValueTuple visitCallExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Call expr)
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{
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scopes.Pop();
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}
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public ValueTuple visitBinaryExpr(ValueTuple context, Binary expr)
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{
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Resolve(context, expr.Left);
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Resolve(context, expr.Right);
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return context;
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}
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public ValueTuple visitCallExpr(ValueTuple context, Call expr)
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{
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Resolve(context, expr.Left);
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Resolve(scopes, expr.Left);
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foreach (var arg in expr.Arguments)
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{
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if (arg is not null)
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{
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Resolve(context, arg);
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Resolve(scopes, arg);
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}
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}
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return context;
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return Void;
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}
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public ValueTuple visitGroupingExpr(ValueTuple context, Grouping expr)
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public ValueTuple visitGroupingExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Grouping expr)
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{
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Resolve(context, expr.Expression);
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return context;
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Resolve(scopes, expr.Expression);
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return Void;
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}
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public ValueTuple visitIfExpr(ValueTuple context, If expr)
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public ValueTuple visitIfExpr(ImmutableStack<ImmutableHashSet<string>> scopes, If expr)
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{
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Resolve(context, expr.Condition);
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Resolve(context, expr.Then);
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Resolve(context, expr.Else);
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return context;
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Resolve(scopes, expr.Condition);
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Resolve(scopes, expr.Then);
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Resolve(scopes, expr.Else);
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return Void;
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}
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public ValueTuple visitIndexerExpr(ValueTuple context, Indexer expr)
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public ValueTuple visitIndexerExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Indexer expr)
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{
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Resolve(context, expr.Left);
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Resolve(context, expr.Index);
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return context;
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Resolve(scopes, expr.Left);
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Resolve(scopes, expr.Index);
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return Void;
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}
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public ValueTuple visitLetExpr(ValueTuple context, Let expr)
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public ValueTuple visitLetExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Let expr)
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{
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var names = new NameCollection();
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foreach (var binding in expr.Bindings)
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@ -161,7 +148,7 @@ class Resolver : IExprVisitor<ValueTuple, ValueTuple>
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}
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}
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BeginScope(names.Names);
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var newScopes = scopes.Push(names.Names);
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// TODO Put the static constructivity check here.
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// For now, just check that a definition only uses names that come before it.
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@ -172,55 +159,54 @@ class Resolver : IExprVisitor<ValueTuple, ValueTuple>
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switch (binding)
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{
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case FuncBinding fb:
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ResolveFunction(context, fb);
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ResolveFunction(newScopes, fb);
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break;
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case VarBinding vb:
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Resolve(context, vb.Value);
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Resolve(newScopes, vb.Value);
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break;
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default:
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throw new Exception("wtf there are no other binding types");
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}
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}
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Resolve(context, expr.Body);
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Resolve(newScopes, expr.Body);
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EndScope();
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return context;
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return Void;
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}
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private void ResolveFunction(ValueTuple context, FuncBinding fb)
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private void ResolveFunction(ImmutableStack<ImmutableHashSet<string>> scopes, FuncBinding fb)
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{
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NameCollection names = new();
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foreach (var param in fb.Params)
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{
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param.accept(names, PatternNameCollector.Instance);
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}
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ResolveInNewScope(context, names.Names, fb.Value);
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Resolve(scopes, names.Names, fb.Value);
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}
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public ValueTuple visitListExpr(ValueTuple context, List expr)
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public ValueTuple visitListExpr(ImmutableStack<ImmutableHashSet<string>> scopes, List expr)
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{
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foreach (var element in expr.Elements)
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{
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Resolve(context, element);
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Resolve(scopes, element);
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}
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return context;
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return Void;
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}
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public ValueTuple visitLiteralExpr(ValueTuple context, Literal expr)
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public ValueTuple visitLiteralExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Literal expr)
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{
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return context;
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return Void;
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}
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public ValueTuple visitRecordExpr(ValueTuple context, Record expr)
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public ValueTuple visitRecordExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Record expr)
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{
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if (expr.Base is not null)
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{
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Resolve(context, expr.Base.Value);
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Resolve(scopes, expr.Base.Value);
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foreach (var update in expr.Base.Updates)
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{
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if (update.Value is not null)
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{
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Resolve(context, update.Value);
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Resolve(scopes, update.Value);
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}
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else
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{
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@ -232,66 +218,76 @@ class Resolver : IExprVisitor<ValueTuple, ValueTuple>
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{
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if (extension.Value is not null)
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{
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Resolve(context, extension.Value);
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Resolve(scopes, extension.Value);
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}
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else
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{
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// TODO Resolve extension.Name like a var expression.
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}
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}
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return context;
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return Void;
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}
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public ValueTuple visitSelectorExpr(ValueTuple context, Selector expr)
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public ValueTuple visitSelectorExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Selector expr)
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{
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Resolve(context, expr.Left);
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return context;
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Resolve(scopes, expr.Left);
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return Void;
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}
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public ValueTuple visitSequenceExpr(ValueTuple context, Sequence expr)
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public ValueTuple visitSequenceExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Sequence expr)
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{
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Resolve(context, expr.Left);
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Resolve(context, expr.Right);
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return context;
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Resolve(scopes, expr.Left);
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Resolve(scopes, expr.Right);
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return Void;
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}
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public ValueTuple visitUnaryExpr(ValueTuple context, Unary expr)
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public ValueTuple visitUnaryExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Unary expr)
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{
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Resolve(context, expr.Right);
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return context;
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Resolve(scopes, expr.Right);
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return Void;
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}
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public ValueTuple visitVariableExpr(ValueTuple context, Variable expr)
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public ValueTuple visitVariableExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Variable expr)
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{
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ResolveLocal(expr, expr.Value);
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return context;
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ResolveLocal(scopes, expr, expr.Value);
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return Void;
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}
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private void ResolveLocal(Expr expr, Token name)
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private void ResolveLocal(ImmutableStack<ImmutableHashSet<string>> scopes, Expr expr, Token name)
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{
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// TODO I can't peek past the top element of the stack (as is correct for a stack).
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// Switch to an immutable stack so I can just pop stuff off, or switch to a list.
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throw new NotImplementedException();
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int depth = 0;
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while (!scopes.IsEmpty)
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{
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scopes = scopes.Pop(out var scope);
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if (scope.Contains((string)name.Literal!))
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{
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Interpreter.Resolve(expr, depth);
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return;
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}
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depth++;
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}
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// At this point, it must be a global. I don't like that we leave that resolution for runtime.
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// TODO Don't leave that resolution for runtime.
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}
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public ValueTuple visitVariantExpr(ValueTuple context, Variant expr)
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public ValueTuple visitVariantExpr(ImmutableStack<ImmutableHashSet<string>> scopes, Variant expr)
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{
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if (expr.Argument is not null)
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{
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Resolve(context, expr.Argument);
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Resolve(scopes, expr.Argument);
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}
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return context;
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return Void;
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}
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public ValueTuple visitWhenExpr(ValueTuple context, When expr)
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public ValueTuple visitWhenExpr(ImmutableStack<ImmutableHashSet<string>> scopes, When expr)
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{
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Resolve(context, expr.Head);
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Resolve(scopes, expr.Head);
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foreach (var _case in expr.Cases)
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{
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var names = new NameCollection();
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_case.Pattern.accept(names, PatternNameCollector.Instance);
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ResolveInNewScope(context, names.Names, _case.Value);
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Resolve(scopes, names.Names, _case.Value);
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}
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return context;
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return Void;
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}
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}
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