//SourceCode ::= Statement+
static public (SourceCode, string) parseSourceCode(ref lexer.Lexer Lexer)
{
SourceCode sourceCode = new SourceCode();
string error;
sourceCode.LineNum = Lexer.GetLineNum();
(sourceCode.Statements, error) = parseStatements(ref Lexer);
if (error != null)
{
return(sourceCode, error);
}
return(sourceCode, null);
}
//Variable ::= "$" Name Ignored
static public (Variable, string) parseVariable(ref lexer.Lexer Lexer)
{
Variable variable = new Variable();
string error;
variable.LineNum = Lexer.GetLineNum();
Lexer.NextTokenIs(lexer.TOKEN_VAR_PREFIX);
(variable.Name, error) = parseName(ref Lexer);
if (error != null)
{
return(variable, error);
}
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
return(variable, null);
}
//Print ::= "print" "(" Ignored Variable Ignored ")" Ignored
static public (Print, string) parsePrint(ref lexer.Lexer Lexer)
{
Print print = new Print();
string error;
print.LineNum = Lexer.GetLineNum();
Lexer.NextTokenIs(lexer.TOKEN_PRINT);
Lexer.NextTokenIs(lexer.TOKEN_LEFT_PAREN);
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
(print.Variable, error) = parseVariable(ref Lexer);
if (error != null)
{
return(print, error);
}
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
Lexer.NextTokenIs(lexer.TOKEN_RIGHT_PAREN);
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
return(print, null);
}
//Assignment ::= Variable Ignored "=" Ignored String Ignored
static public (Assignment, string) parseAssignment(ref lexer.Lexer Lexer)
{
Assignment assignment = new Assignment();
string error;
assignment.LineNum = Lexer.GetLineNum();
(assignment.Variable, error) = parseVariable(ref Lexer);
if (error != null)
{
return(assignment, error);
}
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
Lexer.NextTokenIs(lexer.TOKEN_EQUAL);
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
(assignment.String, error) = parseString(ref Lexer);
if (error != null)
{
return(assignment, error);
}
Lexer.LookAheadAndSkip(lexer.TOKEN_IGNORED);
return(assignment, null);
}