/// <summary>
/// Declares a variable or function in this scope. This will be initialized with the value
/// of the given expression.
/// </summary>
/// <param name="keyword"> The keyword that was used to declare the variable (var, let or
/// const). </param>
/// <param name="name"> The name of the variable. </param>
/// <param name="hoistedFunction"> The function value to hoist to the top of the scope.
/// Should be <c>null</c> for everything except function declarations. </param>
/// <returns> A reference to the variable that was declared. </returns>
internal void DeclareVariable(KeywordToken keyword, string name, FunctionExpression hoistedFunction = null)
{
if (name == null)
{
throw new ArgumentNullException(nameof(name));
}
// If variables cannot be declared in the scope, try the parent scope instead.
var declarationScope = this;
if (keyword == KeywordToken.Var)
{
while (declarationScope != null && (declarationScope.Type == ScopeType.Block || declarationScope.Type == ScopeType.With))
{
declarationScope = declarationScope.ParentScope;
}
}
if (declarationScope != null && !declarationScope.variables.ContainsKey(name))
{
// This is a local variable that has not been declared before.
var variable = new DeclaredVariable()
{
Scope = declarationScope,
Index = declarationScope.variables.Count,
Keyword = keyword,
Name = name,
};
declarationScope.variables.Add(name, variable);
}
if (hoistedFunction != null)
{
var hoistedScope = this;
while (hoistedScope != null && hoistedScope.Type == ScopeType.Block)
{
hoistedScope = hoistedScope.ParentScope;
}
if (hoistedScope.hoistedFunctions == null)
{
hoistedScope.hoistedFunctions = new Dictionary <string, FunctionExpression>();
}
hoistedScope.hoistedFunctions[name] = hoistedFunction;
}
}
/// <summary>
/// Declares a variable or function in this scope. This will be initialized with the value
/// of the given expression.
/// </summary>
/// <param name="name"> The name of the variable. </param>
/// <param name="valueAtTopOfScope"> The value of the variable at the top of the scope.
/// Can be <c>null</c> to indicate the variable does not need initializing. </param>
/// <param name="writable"> <c>true</c> if the variable can be modified; <c>false</c>
/// otherwise. Defaults to <c>true</c>. </param>
/// <param name="deletable"> <c>true</c> if the variable can be deleted; <c>false</c>
/// otherwise. Defaults to <c>true</c>. </param>
/// <returns> A reference to the variable that was declared. </returns>
internal virtual DeclaredVariable DeclareVariable(string name, Expression valueAtTopOfScope = null, bool writable = true, bool deletable = false)
{
if (name == null)
{
throw new ArgumentNullException(nameof(name));
}
// If variables cannot be declared in the scope, try the parent scope instead.
if (this.CanDeclareVariables == false)
{
if (this.ParentScope == null)
{
throw new InvalidOperationException("Invalid scope chain.");
}
return(this.ParentScope.DeclareVariable(name, valueAtTopOfScope, writable, deletable));
}
DeclaredVariable variable;
this.variables.TryGetValue(name, out variable);
if (variable == null)
{
// This is a local variable that has not been declared before.
variable = new DeclaredVariable()
{
Scope = this, Index = this.variables.Count, Name = name, Writable = writable, Deletable = deletable
};
this.variables.Add(name, variable);
}
// Set the initial value, if one was provided.
if (valueAtTopOfScope != null)
{
// Function expressions override literals.
if ((valueAtTopOfScope is LiteralExpression && variable.ValueAtTopOfScope is FunctionExpression) == false)
{
variable.ValueAtTopOfScope = valueAtTopOfScope;
}
}
return(variable);
}
/// <summary>
/// Declares a variable or function in this scope. This will be initialized with the value
/// of the given expression.
/// </summary>
/// <param name="name"> The name of the variable. </param>
/// <param name="valueAtTopOfScope"> The value of the variable at the top of the scope.
/// Can be <c>null</c> to indicate the variable does not need initializing. </param>
/// <param name="writable"> <c>true</c> if the variable can be modified; <c>false</c>
/// otherwise. Defaults to <c>true</c>. </param>
/// <param name="deletable"> <c>true</c> if the variable can be deleted; <c>false</c>
/// otherwise. Defaults to <c>true</c>. </param>
/// <returns> A reference to the variable that was declared. </returns>
internal virtual DeclaredVariable DeclareVariable(string name, Expression valueAtTopOfScope = null, bool writable = true, bool deletable = false)
{
if (name == null)
throw new ArgumentNullException("name");
// If variables cannot be declared in the scope, try the parent scope instead.
if (this.CanDeclareVariables == false)
{
if (this.ParentScope == null)
throw new InvalidOperationException("Invalid scope chain.");
return this.ParentScope.DeclareVariable(name, valueAtTopOfScope, writable, deletable);
}
DeclaredVariable variable;
this.variables.TryGetValue(name, out variable);
if (variable == null)
{
// This is a local variable that has not been declared before.
variable = new DeclaredVariable() { Scope = this, Index = this.variables.Count, Name = name, Writable = writable, Deletable = deletable };
this.variables.Add(name, variable);
}
// Set the initial value, if one was provided.
if (valueAtTopOfScope != null)
{
// Function expressions override literals.
if ((valueAtTopOfScope is LiteralExpression && variable.ValueAtTopOfScope is FunctionExpression) == false)
variable.ValueAtTopOfScope = valueAtTopOfScope;
}
return variable;
}
