// This allows base Code class to construct a sequence.
public static SequenceCode BuildFromTokens(
List <Token> tokens,
string sourceTextForErrorMessages,
string sourceNameForErrorMessages)
{
LookAhead Look = new LookAhead(tokens);
var sequenceCode = GetSequence();
Look.Require(TokenType.EndOfSourceText, sourceTextForErrorMessages, sourceNameForErrorMessages);
sequenceCode.SourceText = sourceTextForErrorMessages;
return(sequenceCode);
// Some local helper functions.
SequenceCode GetSequence()
{
var result = new SequenceCode();
while (true)
{
if (Look.Got(TokenType.Characters))
{
result.Codes.Add(new CharacterCode(Look.Value));
}
else if (Look.Got(TokenType.Special))
{
// Ex. [he]
result.Codes.Add(new SpecialCode(Look.Value));
}
else if (Look.Got(TokenType.Merge))
{
// [merge]
// [merge sceneId]
string sceneId = null;
if (Look.Got(TokenType.Id))
{
sceneId = Look.Value;
}
result.Codes.Add(new MergeCode(sceneId));
}
else if (Look.Got(TokenType.Return))
{
// [return]
result.Codes.Add(new ReturnCode());
}
else if (Look.Got(TokenType.Scene))
{
// [scene soundsLikeAScam]
Look.Require(TokenType.Id, sourceTextForErrorMessages, sourceNameForErrorMessages);
result.Codes.Add(new SceneCode(Look.Value));
}
else if (Look.Got(TokenType.Score) || Look.Got(TokenType.Sort))
{
// SCORE ID [, ID...]
// SORT ID [, ID...]
var sortOnly = Look.Type == TokenType.Sort;
List <string> ids = new List <string>();
do
{
Look.Require(TokenType.Id, sourceTextForErrorMessages, sourceNameForErrorMessages);
ids.Add(Look.Value);
} while (Look.Got(TokenType.Comma));
result.Codes.Add(new ScoreCode(ids, sortOnly));
}
else if (Look.Got(TokenType.Text))
{
Look.Require(TokenType.Id, sourceTextForErrorMessages, sourceNameForErrorMessages);
string id = Look.Value;
string text = "";
if (Look.Got(TokenType.Characters))
{
text = Look.Value;
}
Look.Require(TokenType.End, sourceTextForErrorMessages, sourceNameForErrorMessages);
result.Codes.Add(new TextCode(id, text));
}
else if (Look.Got(TokenType.Set))
{
result.Codes.Add(new SetCode(GetExpressions(false)));
}
else if (Look.Got(TokenType.When))
{
if (Look.Got(TokenType.Else))
{
result.Codes.Add(new WhenElseCode());
}
else
{
result.Codes.Add(new WhenCode(GetExpressions(true)));
}
}
else if (Look.Got(TokenType.If))
{
var ifCode = GetIf();
result.Codes.Add(ifCode);
// The whole if/or case statement is terminated by 'end'.
Look.Require(TokenType.End, sourceTextForErrorMessages, sourceNameForErrorMessages);
}
else
{
// Hopefully the token we've been looking at is something the caller is expecting to see next (i.e. end of source text).
return(result);
}
}
}
List <Expression> GetExpressions(
bool allowNotEqual)
{
// ID
// NOT ID
// ID=ID
// NOT ID=ID
// allowNotEqual: [when not a=b] makes sense. But [set not a=b] doesn't mean anything.
var result = new List <Expression>();
do
{
var not = Look.Got(TokenType.Not);
Look.Require(TokenType.Id, sourceTextForErrorMessages, sourceNameForErrorMessages);
var leftId = Look.Value;
string rightId = null;
if (allowNotEqual || !not)
{
if (Look.Got(TokenType.Equal))
{
Look.Require(TokenType.Id, sourceTextForErrorMessages, sourceNameForErrorMessages);
rightId = Look.Value;
}
}
result.Add(new Expression(not, leftId, rightId));
} while (Look.Got(TokenType.Comma));
return(result);
}
/* This flat 'if' sequence with 'or' (which is like 'elif' but more Englishy)...
*
* [if reaction=Flee]
* A
* [or reaction=Escape]
* B
* [else]
* C
* [end]
*
* ...is equivalent to this nested sequence:
*
* if reaction=Flee
* A
* else
* if reaction=Escape
* B
* else
* C
*/
IfCode GetIf()
{
// This is called after getting 'if' or 'or'.
// First get the expression. It's like one of these:
// [if brave]
// [if not killedInspector]
var expressions = GetExpressions(true);
var trueCode = GetSequence();
Code falseCode = null;
if (Look.Got(TokenType.Else))
{
falseCode = GetSequence();
}
else if (Look.Got(TokenType.Or))
{
falseCode = GetIf();
}
// Otherwise must be 'end'. Let caller handle it.
return(new IfCode(expressions, trueCode, falseCode));
}
}
public CodeTree(
string sourceText,
string sourceNameForErrorMessages,
Dictionary <string, Setting> settings)
{
// Compile the text to a code tree.
SourceText = sourceText;
var tokenList = new TokenList(sourceText, sourceNameForErrorMessages, settings);
var Look = new LookAhead(tokenList);
RootCode = ParseSequence();
Look.Require(TokenType.EndOfSourceText, sourceText, sourceNameForErrorMessages);
// Some local helper functions.
SequenceCode ParseSequence()
{
var codes = new List <Code>();
while (true)
{
if (Look.Got(TokenType.Characters))
{
codes.Add(new CharacterCode(Look.Value));
}
else if (Look.Got(TokenType.SpecialId))
{
// Ex. [he]
codes.Add(new SpecialCode(Look.Value));
}
else if (Look.Got(TokenType.Merge))
{
// [merge]
// [merge sceneId]
string?sceneId = Look.Got(TokenType.Id) ? Look.Value : null;
codes.Add(new MergeCode(sceneId));
}
else if (Look.Got(TokenType.Return))
{
// [return]
codes.Add(new ReturnCode());
}
else if (Look.Got(TokenType.Scene))
{
// [scene soundsLikeAScam]
Look.Require(TokenType.Id, sourceText, sourceNameForErrorMessages);
codes.Add(new SceneCode(Look.Value));
}
else if (Look.Got(TokenType.Score) || Look.Got(TokenType.Sort))
{
// SCORE SCOREID [, SCOREID...]
// SORT SCOREID [, ID...]
var sortOnly = Look.Type == TokenType.Sort;
List <string> ids = new List <string>();
do
{
Look.Require(TokenType.ScoreId, sourceText, sourceNameForErrorMessages);
ids.Add(Look.Value);
} while (Look.Got(TokenType.Comma));
codes.Add(new ScoreCode(ids, sortOnly));
}
else if (Look.Got(TokenType.Text))
{
Look.Require(TokenType.Id, sourceText, sourceNameForErrorMessages);
string id = Look.Value;
string text = "";
if (Look.Got(TokenType.Characters))
{
text = Look.Value;
}
Look.Require(TokenType.End, sourceText, sourceNameForErrorMessages);
codes.Add(new TextCode(id, text));
}
else if (Look.Got(TokenType.Set))
{
codes.Add(new SetCode(ParseExpressions(false)));
}
else if (Look.Got(TokenType.When))
{
if (Look.Got(TokenType.Else))
{
codes.Add(new WhenElseCode());
}
else
{
codes.Add(new WhenCode(ParseExpressions(true)));
}
}
else if (Look.Got(TokenType.If))
{
var ifCode = ParseIf();
codes.Add(ifCode);
// The whole if/or case statement is terminated by 'end'.
Look.Require(TokenType.End, sourceText, sourceNameForErrorMessages);
}
else
{
// Hopefully the token we've been looking at is something the caller is expecting to see next (i.e. end of source text).
return(new SequenceCode(codes));
}
}
}
List <Expression> ParseExpressions(
bool allowNotEqual)
{
// BOOLEANID
// NOT BOOLEANID
// STRINGID=ID
// NOT STRINGID=ID
// allowNotEqual: [when not a=b] makes sense. But [set not a=b] doesn't mean anything.
var result = new List <Expression>();
do
{
var not = Look.Got(TokenType.Not);
string leftId;
string?rightId = null;
if (Look.Got(TokenType.BooleanId) || Look.Got(TokenType.ScoreId))
{
leftId = Look.Value;
}
else
{
if (not && !allowNotEqual)
{
throw new InvalidOperationException(string.Format($"file {sourceNameForErrorMessages}: unexpected {TokenType.Not} in\n{sourceText}"));
}
Look.Require(TokenType.StringId, sourceText, sourceNameForErrorMessages);
leftId = Look.Value;
Look.Require(TokenType.Equal, sourceText, sourceNameForErrorMessages);
Look.Require(TokenType.Id, sourceText, sourceNameForErrorMessages);
rightId = Look.Value;
}
result.Add(new Expression(not, leftId, rightId));
} while (Look.Got(TokenType.Comma));
return(result);
}
/* This flat 'if' sequence with 'or' (which is like 'elif' but more Englishy)...
*
* [if reaction=Flee]
* A
* [or reaction=Escape]
* B
* [else]
* C
* [end]
*
* ...is equivalent to this nested sequence:
*
* if reaction=Flee
* A
* else
* if reaction=Escape
* B
* else
* C
*/
IfCode ParseIf()
{
// This is called after getting 'if' or 'or'.
// First get the expression. It's like one of these:
// [if brave]
// [if not killedInspector]
var expressions = ParseExpressions(true);
var trueCode = ParseSequence();
Code?falseCode = null;
if (Look.Got(TokenType.Else))
{
falseCode = ParseSequence();
}
else if (Look.Got(TokenType.Or))
{
falseCode = ParseIf();
}
// Otherwise must be 'end'. Let caller handle it.
return(new IfCode(expressions, trueCode, falseCode));
}
}