/// <summary>
/// Matches a <c>FunctionDeclaration</c> non-terminal.
/// </summary>
/// <returns><c>true</c> if the <c>FunctionDeclaration</c> was matched successfully; otherwise, <c>false</c>.</returns>
/// <remarks>
/// The non-terminal can start with: <c>Function</c>.
/// </remarks>
protected virtual bool MatchFunctionDeclaration(out Statement statement) {
statement = null;
int start = this.LookAheadToken.StartOffset;
string description = this.GetDescription();
bool expectsSelf;
if (!this.Match(LuatTokenId.Function))
return false;
Expression name;
if (!this.MatchFunctionName(out name, out expectsSelf))
return false;
Function function;
if (!this.MatchFunctionBody(out function))
return false;
AssignmentStatement assignment = new AssignmentStatement();
assignment.Variables.Add( name );
assignment.Values.Add( function );
// Use the preceding comment as the function description
function.Description = (null != description)
? description.Trim( '\n', '\r' )
: null;
function.ExpectsSelf = expectsSelf;
// Mark the LHS expression as being assigned.
// This alters the way certain variables are resolved.
name.IsLHSOfAssignment = true;
assignment.StartOffset = start; assignment.EndOffset = this.Token.EndOffset;
statement = assignment;
return true;
}
/// <summary>
/// Matches a <c>AssignmentOrFunctionCall</c> non-terminal.
/// </summary>
/// <returns><c>true</c> if the <c>AssignmentOrFunctionCall</c> was matched successfully; otherwise, <c>false</c>.</returns>
/// <remarks>
/// The non-terminal can start with: <c>OpenParenthesis</c>, <c>OpenCurlyBrace</c>, <c>Identifier</c>, <c>TripleDot</c>, <c>Nil</c>, <c>False</c>, <c>True</c>, <c>Number</c>, <c>Subtraction</c>, <c>Not</c>, <c>Hash</c>, <c>String</c>.
/// </remarks>
protected virtual bool MatchAssignmentOrFunctionCall(out Statement statement) {
Expression expression = null;
statement = null;
int start = this.LookAheadToken.StartOffset;
if (!this.MatchExpressionNoFunction(out expression))
return false;
if ( IsFunctionCall( expression ) )
{
statement = new ExpressionStatement( expression );
return true;
}
AssignmentStatement assignment = new AssignmentStatement();
statement = assignment;
assignment.Variables.Add( expression );
while (this.TokenIs(this.LookAheadToken, LuatTokenId.Comma)) {
if (!this.Match(LuatTokenId.Comma))
return false;
if (!this.MatchExpressionNoFunction(out expression))
return false;
assignment.Variables.Add( expression );
}
if (!this.Match(LuatTokenId.Assignment))
return false;
if (!this.MatchExpressionList(assignment.Values))
return false;
foreach( Expression variable in assignment.Variables )
{
// Mark the LHS expression as being assigned.
// This alters the way certain variables are resolved.
variable.IsLHSOfAssignment = true;
if( false == IsVariable( variable ) )
{
// First expression was not a variable or a function call.
// Invalid statement
string message = "The left-hand side of an assignment must be a variable";
compilationUnit.SyntaxErrors.Add(new SyntaxError( variable.TextRange, message ) );
}
}
assignment.StartOffset = start;
assignment.EndOffset = this.Token.EndOffset;
return true;
}
/// <summary>
/// Matches a <c>LocalSuffix</c> non-terminal.
/// </summary>
/// <returns><c>true</c> if the <c>LocalSuffix</c> was matched successfully; otherwise, <c>false</c>.</returns>
/// <remarks>
/// The non-terminal can start with: <c>Function</c>, <c>Identifier</c>.
/// </remarks>
protected virtual bool MatchLocalSuffix(out Statement statement) {
statement = null;
AssignmentStatement assignment = new AssignmentStatement();
assignment.IsLocal = true;
Identifier type = null;
if (this.TokenIs(this.LookAheadToken, LuatTokenId.Identifier)) {
if (!this.MatchVariableList(assignment.Variables))
return false;
if (this.TokenIs(this.LookAheadToken, LuatTokenId.Colon)) {
if (!this.Match(LuatTokenId.Colon))
return false;
if (!this.MatchIdentifier(out type))
return false;
}
if (this.TokenIs(this.LookAheadToken, LuatTokenId.Assignment)) {
if (!this.Match(LuatTokenId.Assignment))
return false;
if (!this.MatchExpressionList(assignment.Values))
return false;
}
}
else if (this.TokenIs(this.LookAheadToken, LuatTokenId.Function)) {
if (!this.Match(LuatTokenId.Function))
return false;
Expression variableNode;
if (!this.MatchVariable(out variableNode))
return false;
Function function;
if (!this.MatchFunctionBody(out function))
return false;
VariableExpression variableExpression = variableNode as VariableExpression;
assignment.Variables.Add( variableNode );
assignment.Values.Add( function );
}
else
return false;
foreach ( VariableExpression v in assignment.Variables )
{
v.IsLHSOfAssignment = true;
v.IsLocal = true;
v.Type = type == null ? null : type.Text;
}
statement = assignment;
return true;
}