public static ReadOnlyMemory<char> ChopNewLine(this ReadOnlyMemory<char> literal)
{
var lastChar = literal.SafeGetChar(literal.Length - 1);
if (lastChar == '\r' || lastChar == '\n')
{
return literal.Span.SafeCharEquals(literal.Length - 2, '\r')
? literal.Slice(0, literal.Length - 2)
: literal.Slice(0, literal.Length - 1);
}
return literal;
}
// {{#name}} {{else if a=b}} {{else}} {{/name}}
// ^
// returns ^ ^
static ReadOnlyMemory <char> ParseStatementBody(this ReadOnlyMemory <char> literal, ReadOnlyMemory <char> blockName, out List <PageFragment> body)
{
var inStatements = 0;
var pos = 0;
while (true)
{
pos = literal.IndexOf("{{", pos);
if (pos == -1)
{
throw new SyntaxErrorException($"End block for '{blockName}' not found.");
}
var c = literal.SafeGetChar(pos + 2);
if (c == '#')
{
inStatements++;
pos = literal.IndexOf("}}", pos) + 2; //end of expression
continue;
}
if (c == '/')
{
if (inStatements == 0)
{
literal.Slice(pos + 2 + 1).ParseVarName(out var name);
if (name.EqualsOrdinal(blockName))
{
body = ParseTemplatePage(literal.Slice(0, pos).TrimFirstNewLine());
return(literal.Slice(pos));
}
}
inStatements--;
}
else if (literal.Slice(pos + 2).StartsWith("else"))
{
if (inStatements == 0)
{
body = ParseTemplatePage(literal.Slice(0, pos).TrimFirstNewLine());
return(literal.Slice(pos));
}
}
pos += 2;
}
}
// {{else if a=b}} {{else}} {{/name}}
// ^
// returns ^ ^
static ReadOnlyMemory <char> ParseElseStatement(this ReadOnlyMemory <char> literal, string blockName, out PageElseBlock statement)
{
var inStatements = 0;
var pos = 0;
statement = null;
var statementPos = -1;
var elseExpr = default(ReadOnlyMemory <char>);
while (true)
{
pos = literal.IndexOf("{{", pos);
if (pos == -1)
{
throw new SyntaxErrorException($"End block for 'else' not found.");
}
var c = literal.SafeGetChar(pos + 2);
if (c == '#')
{
inStatements++;
pos = literal.IndexOf("}}", pos) + 2; //end of expression
}
else if (c == '/')
{
if (inStatements == 0)
{
literal.Slice(pos + 2 + 1).ParseVarName(out var name);
if (name.EqualsOrdinal(blockName))
{
var body = ParseTemplatePage(literal.Slice(statementPos, pos - statementPos).TrimFirstNewLine());
statement = new PageElseBlock(elseExpr, body);
return(literal.Slice(pos));
}
}
inStatements--;
}
else if (literal.Slice(pos + 2).StartsWith("else"))
{
if (inStatements == 0)
{
if (statementPos >= 0)
{
var bodyText = literal.Slice(statementPos, pos - statementPos).TrimFirstNewLine();
var body = ParseTemplatePage(bodyText);
statement = new PageElseBlock(elseExpr, body);
return(literal.Slice(pos));
}
var endExprPos = literal.IndexOf("}}", pos);
if (endExprPos == -1)
{
throw new SyntaxErrorException($"End expression for 'else' not found.");
}
var exprStartPos = pos + 2 + 4; //= {{else...
elseExpr = literal.Slice(exprStartPos, endExprPos - exprStartPos).Trim();
statementPos = endExprPos + 2;
}
}
pos += 2;
}
}
