// Parse:
// statement --> assign-statement
// --> update-statement
// --> HALT
//
// update-statement --> UPDATE ( "path" )
// --> UPDATE ( postfix-expr )
private RuleAction ParseStatement(ParserContext parserContext)
{
RuleAction action = null;
Token statementToken = parserContext.CurrentToken;
if (statementToken.TokenID == TokenID.Halt)
{
parserContext.NextToken(); // eat the "halt"
action = new RuleHaltAction();
parserContext.exprPositions[action] = statementToken.StartPosition;
ValidateAction(parserContext, action);
}
else if (statementToken.TokenID == TokenID.Update)
{
string message;
parserContext.NextToken(); // eat the "update"
if (parserContext.CurrentToken.TokenID != TokenID.LParen)
{
message = string.Format(CultureInfo.CurrentCulture, Messages.Parser_MissingLparenAfterCommand, "UPDATE");
throw new RuleSyntaxException(ErrorNumbers.Error_MissingLparenAfterCommand, message, parserContext.CurrentToken.StartPosition);
}
parserContext.NextToken(); // Eat the "("
string pathString = null;
Token updateArgToken = parserContext.CurrentToken;
if (updateArgToken.TokenID == TokenID.StringLiteral)
{
// Treat UPDATE("foo/bar") as a literal path.
pathString = (string)updateArgToken.Value;
parserContext.NextToken(); // Eat the path string.
}
else
{
CodeExpression pathExpr = ParsePostfixExpression(parserContext, true, ValueCheck.Read);
RuleAnalysis analysis = new RuleAnalysis(validation, true);
RuleExpressionWalker.AnalyzeUsage(analysis, pathExpr, false, true, null);
ICollection<string> paths = analysis.GetSymbols();
if (paths.Count == 0 || paths.Count > 1)
{
// The expression did not modify anything, or it modified more than one.
throw new RuleSyntaxException(ErrorNumbers.Error_InvalidUpdateExpression, Messages.Parser_InvalidUpdateExpression, updateArgToken.StartPosition);
}
else
{
IEnumerator<string> enumerator = paths.GetEnumerator();
enumerator.MoveNext();
pathString = enumerator.Current;
}
}
if (parserContext.CurrentToken.TokenID != TokenID.RParen)
throw new RuleSyntaxException(ErrorNumbers.Error_MissingRParenAfterArgumentList, Messages.Parser_MissingRParenAfterArgumentList, parserContext.CurrentToken.StartPosition);
parserContext.NextToken(); // Eat the ")"
action = new RuleUpdateAction((string)pathString);
parserContext.exprPositions[action] = statementToken.StartPosition;
ValidateAction(parserContext, action);
}
else
{
// Try to parse a custom RuleAction.
int savedTokenState = parserContext.SaveCurrentToken();
Type type = TryParseTypeSpecifier(parserContext, false);
if (type != null &&
parserContext.CurrentToken.TokenID == TokenID.LParen &&
TypeProvider.IsAssignable(typeof(RuleAction), type))
{
// The statement started with a "type (", and the type derived from RuleAction.
// This is a custom rule action.
int lparenPosition = parserContext.CurrentToken.StartPosition;
parserContext.NextToken(); // Eat the '('
List<CodeExpression> arguments = ParseArgumentList(parserContext);
action = (RuleAction)ConstructCustomType(type, arguments, lparenPosition);
parserContext.exprPositions[action] = statementToken.StartPosition;
ValidateAction(parserContext, action);
}
else
{
// It wasn't a custom action.
// In some cases it may have looked like one up to a point, such as:
//
// MyType.MyMember(
//
// but "MyMember" is a static method.
// Reset the scanner state, and re-parse as an assignment.
parserContext.RestoreCurrentToken(savedTokenState);
CodeStatement statement = ParseAssignmentStatement(parserContext);
if (statement != null)
{
// Create a rule statement action around it. No need to validate it, as
// the underlying CodeDom statement has been validated already.
action = new RuleStatementAction(statement);
}
}
}
return action;
}
private RuleAction ParseStatement(ParserContext parserContext)
{
RuleAction action = null;
Token currentToken = parserContext.CurrentToken;
if (currentToken.TokenID == TokenID.Halt)
{
parserContext.NextToken();
action = new RuleHaltAction();
parserContext.exprPositions[action] = currentToken.StartPosition;
this.ValidateAction(parserContext, action);
return action;
}
if (currentToken.TokenID == TokenID.Update)
{
parserContext.NextToken();
if (parserContext.CurrentToken.TokenID != TokenID.LParen)
{
string message = string.Format(CultureInfo.CurrentCulture, Messages.Parser_MissingLparenAfterCommand, new object[] { "UPDATE" });
throw new RuleSyntaxException(0x180, message, parserContext.CurrentToken.StartPosition);
}
parserContext.NextToken();
string path = null;
Token token2 = parserContext.CurrentToken;
if (token2.TokenID == TokenID.StringLiteral)
{
path = (string) token2.Value;
parserContext.NextToken();
}
else
{
CodeExpression expression = this.ParsePostfixExpression(parserContext, true, ValueCheck.Read);
RuleAnalysis analysis = new RuleAnalysis(this.validation, true);
RuleExpressionWalker.AnalyzeUsage(analysis, expression, false, true, null);
ICollection<string> symbols = analysis.GetSymbols();
if ((symbols.Count == 0) || (symbols.Count > 1))
{
throw new RuleSyntaxException(0x181, Messages.Parser_InvalidUpdateExpression, token2.StartPosition);
}
IEnumerator<string> enumerator = symbols.GetEnumerator();
enumerator.MoveNext();
path = enumerator.Current;
}
if (parserContext.CurrentToken.TokenID != TokenID.RParen)
{
throw new RuleSyntaxException(0x182, Messages.Parser_MissingRParenAfterArgumentList, parserContext.CurrentToken.StartPosition);
}
parserContext.NextToken();
action = new RuleUpdateAction(path);
parserContext.exprPositions[action] = currentToken.StartPosition;
this.ValidateAction(parserContext, action);
return action;
}
int tokenValue = parserContext.SaveCurrentToken();
Type fromType = this.TryParseTypeSpecifier(parserContext, false);
if (((fromType != null) && (parserContext.CurrentToken.TokenID == TokenID.LParen)) && TypeProvider.IsAssignable(typeof(RuleAction), fromType))
{
int startPosition = parserContext.CurrentToken.StartPosition;
parserContext.NextToken();
List<CodeExpression> arguments = this.ParseArgumentList(parserContext);
action = (RuleAction) this.ConstructCustomType(fromType, arguments, startPosition);
parserContext.exprPositions[action] = currentToken.StartPosition;
this.ValidateAction(parserContext, action);
return action;
}
parserContext.RestoreCurrentToken(tokenValue);
CodeStatement codeDomStatement = this.ParseAssignmentStatement(parserContext);
if (codeDomStatement != null)
{
action = new RuleStatementAction(codeDomStatement);
}
return action;
}