private static void FromSetExpression(ChainBuilder chain, object[] expression, string sourceFile, int lineNumber)
{
if (expression.Length < 4 || !expression[2].Equals("=") || !(expression[1] is string name))
{
throw new SyntaxError(
$"A set command has the format [set name = value], which doesn't match the expression {Writer.TermToString(expression)}.",
sourceFile, lineNumber);
}
if (DefinitionStream.IsGlobalVariableName(name))
{
chain.AddStep(new AssignmentStep(StateVariableName.Named(name),
FunctionalExpressionParser.FromTuple(chain.CanonicalizeArglist(expression), 3, sourceFile,
lineNumber),
null));
}
else if (DefinitionStream.IsLocalVariableName(name))
{
chain.AddStep(new AssignmentStep(chain.GetLocal(name),
FunctionalExpressionParser.FromTuple(chain.CanonicalizeArglist(expression), 3, sourceFile,
lineNumber),
null));
}
else
{
throw new SyntaxError(
$"A set command can only update a variable; it can't update {expression[1]}",
sourceFile, lineNumber);
}
}