void BadNestedTerminationHandler(Parsed.Object terminatingObj)
{
Conditional conditional = null;
for (var ancestor = terminatingObj.parent; ancestor != null; ancestor = ancestor.parent)
{
if (ancestor is Sequence || ancestor is Conditional)
{
conditional = ancestor as Conditional;
break;
}
}
var errorMsg = "Choices nested in conditionals or sequences need to explicitly divert afterwards.";
// Tutorialise proper choice syntax if this looks like a single choice within a condition, e.g.
// { condition:
// * choice
// }
if (conditional != null)
{
var numChoices = conditional.FindAll <Choice>().Count;
if (numChoices == 1)
{
errorMsg = "Choices with conditions should be written: '* {condition} choice'. Otherwise, " + errorMsg.ToLower();
}
}
Error(errorMsg, terminatingObj);
}
protected Conditional InnerConditionalContent(Expression initialQueryExpression)
{
List<ConditionalSingleBranch> alternatives;
bool canBeInline = initialQueryExpression != null;
bool isInline = Newline () == null;
if (isInline && !canBeInline) {
return null;
}
// Inline innards
if (isInline) {
alternatives = InlineConditionalBranches ();
}
// Multiline innards
else {
alternatives = MultilineConditionalBranches ();
if (alternatives == null) {
// Allow single piece of content within multi-line expression, e.g.:
// { true:
// Some content that isn't preceded by '-'
// }
if (initialQueryExpression) {
List<Parsed.Object> soleContent = StatementsAtLevel (StatementLevel.InnerBlock);
if (soleContent != null) {
var soleBranch = new ConditionalSingleBranch (soleContent);
alternatives = new List<ConditionalSingleBranch> ();
alternatives.Add (soleBranch);
// Also allow a final "- else:" clause
var elseBranch = Parse(SingleMultilineCondition);
if (elseBranch) {
if (!elseBranch.isElse) {
ErrorWithParsedObject ("Expected an '- else:' clause here rather than an extra condition", elseBranch);
elseBranch.isElse = true;
}
alternatives.Add (elseBranch);
}
}
}
// Still null?
if (alternatives == null) {
return null;
}
}
// Like a switch statement
// { initialQueryExpression:
// ... match the expression
// }
if (initialQueryExpression) {
bool earlierBranchesHaveOwnExpression = false;
for (int i = 0; i < alternatives.Count; ++i) {
var branch = alternatives [i];
bool isLast = (i == alternatives.Count - 1);
// Match query
if (branch.ownExpression) {
branch.shouldMatchEquality = true;
earlierBranchesHaveOwnExpression = true;
}
// Else (final branch)
else if (earlierBranchesHaveOwnExpression && isLast) {
branch.isElse = true;
}
// Binary condition:
// { trueOrFalse:
// - when true
// - when false
// }
else {
if (!isLast && alternatives.Count > 2) {
ErrorWithParsedObject ("Only final branch can be an 'else'. Did you miss a ':'?", branch);
} else {
if (i == 0)
branch.isTrueBranch = true;
else
branch.isElse = true;
}
}
}
}
// No initial query, so just a multi-line conditional. e.g.:
// {
// - x > 3: greater than three
// - x == 3: equal to three
// - x < 3: less than three
// }
else {
for (int i = 0; i < alternatives.Count; ++i) {
var alt = alternatives [i];
bool isLast = (i == alternatives.Count - 1);
if (alt.ownExpression == null) {
if (isLast) {
alt.isElse = true;
} else {
if (alt.isElse) {
// Do we ALSO have a valid "else" at the end? Let's report the error there.
var finalClause = alternatives [alternatives.Count - 1];
if (finalClause.isElse) {
ErrorWithParsedObject ("Multiple 'else' cases. Can have a maximum of one, at the end.", finalClause);
} else {
ErrorWithParsedObject ("'else' case in conditional should always be the final one", alt);
}
} else {
ErrorWithParsedObject ("Branch doesn't have condition. Are you missing a ':'? ", alt);
}
}
}
}
if (alternatives.Count == 1 && alternatives [0].ownExpression == null) {
ErrorWithParsedObject ("Condition block with no conditions", alternatives [0]);
}
}
}
// TODO: Come up with water-tight error conditions... it's quite a flexible system!
// e.g.
// - inline conditionals must have exactly 1 or 2 alternatives
// - multiline expression shouldn't have mixed existence of branch-conditions?
if (alternatives == null)
return null;
var cond = new Conditional (initialQueryExpression, alternatives);
return cond;
}