/// <summary>
/// (BNF) declaration : property ':' S* value;
/// (BNF) property : IDENT S*;
/// </summary>
/// <returns></returns>
private CssDeclaration ParseDeclaration()
{
CssDeclaration declaration = new CssDeclaration();
char ch;
while (this.Read(out ch) && (Char.IsWhiteSpace(ch) || ch == ';'))
{
// skip whitespace, and empty declarations
}
// consume property name
switch (ch)
{
case '{':
case ':':
//case ';':
{
throw new SyntaxError("Declaration missing property name", this.reader.FilePath, this.reader.Line, this.reader.Column);
}
case '}':
{
// no more declarations
return(null);
}
}
// read property, starting with current char
int start = this.Position;
while (this.Read(out ch) && !Char.IsWhiteSpace(ch) && ch != ':')
{
// consume property name
switch (ch)
{
case '{':
//case ':':
case ';':
{
throw new SyntaxError("Invalid CSS property name: " + this.Copy(start), this.reader.FilePath, this.reader.Line, this.reader.Column);
}
case '}':
{
this.PutBack();
goto case ';';
}
}
}
declaration.Property = this.Copy(start);
if (Char.IsWhiteSpace(ch))
{
while (this.Read(out ch) && (Char.IsWhiteSpace(ch)))
{
// skip whitespace
}
}
if (ch != ':')
{
// missing the property delim and value
if (ch == ';' || ch == '}')
{
// these are good chars for resyncing
// so put them back on the stream to
// not create subsequent errors
this.PutBack();
}
throw new SyntaxError("Expected <property> : <value>", this.reader.FilePath, this.reader.Line, this.reader.Column);
}
CssValueList value = this.ParseValue();
declaration.Value = value;
return(declaration);
}
/// <summary>
/// (BNF) at-rule : ATKEYWORD S* any* [ block | ';' S* ];
/// </summary>
/// <returns></returns>
/// <remarks>
/// NOTE: each at-rule might parse differently according to CSS3
/// The @media block for example contains a block of statements
/// while other at-rules with a block contain a block of declarations
/// </remarks>
private CssAtRule ParseAtRule()
{
CssAtRule atRule = new CssAtRule();
int start = this.Position + 1;// start with first char of ident
char ch;
while (this.Read(out ch) && !Char.IsWhiteSpace(ch))
{
// continue consuming
}
atRule.Ident = this.Copy(start);
while (this.Read(out ch) && Char.IsWhiteSpace(ch))
{
// consuming whitespace
}
start = this.Position;// start with current char
do
{
switch (ch)
{
case '{': //Block Begin
{
atRule.Value = this.Copy(start);
bool containsRuleSets = String.Equals(atRule.Ident, CssAtRule.MediaIdent, StringComparison.Ordinal);
while (true)
{
while (this.Read(out ch) && Char.IsWhiteSpace(ch))
{
// consume whitespace
}
if (ch == '}')
{
break;
}
try
{
if (containsRuleSets)
{
// includes @media
CssStatement statement = this.ParseStatement();
atRule.Block.Values.Add(statement);
}
else
{
// includes @font-face, @page
this.PutBack();
CssDeclaration declaration = this.ParseDeclaration();
atRule.Block.Values.Add(declaration);
}
}
catch (ParseException ex)
{
this.errors.Add(ex);
while (this.Read(out ch) && ch != '}')
{
// restabilize on block end
}
break;
}
}
return(atRule);
}
case ';': //At-Rule End
{
atRule.Value = this.Copy(start);
return(atRule);
}
}
} while (this.Read(out ch));
throw new UnexpectedEndOfFile("Unclosed At-Rule", this.reader.FilePath, this.reader.Line, this.reader.Column);
}
/// <summary>
/// (BNF) ruleset : selector? '{' S* declaration? [ ';' S* declaration? ]* '}' S*;
/// </summary>
/// <returns></returns>
private CssRuleSet ParseRuleSet()
{
char ch;
CssRuleSet ruleSet = new CssRuleSet();
ParseSelectors:
while (true)
{
try
{
CssSelector selector = this.ParseSelector();
if (selector == null)
{
break;
}
ruleSet.Selectors.Add(selector);
}
catch (ParseException ex)
{
this.errors.Add(ex);
while (this.Read(out ch))
{
// restabalize on next rulset
switch (ch)
{
case ',':
{
// continue parsing rest of Selectors
goto ParseSelectors;
}
case '{':
{
goto ParseDeclarations;
}
//case ':':// keep going
case ';':
case '}':
{
throw new SyntaxError("Invalid selector list", this.reader.FilePath, this.reader.Line, this.reader.Column);
}
}
}
}
}
ParseDeclarations:
while (true)
{
try
{
CssDeclaration declaration = this.ParseDeclaration();
if (declaration == null)
{
break;
}
ruleSet.Declarations.Add(declaration);
}
catch (ParseException ex)
{
this.errors.Add(ex);
while (this.Read(out ch))
{
// restabalize on next declaration
switch (ch)
{
case '{':
{
throw new SyntaxError("Invalid ruleset", this.reader.FilePath, this.reader.Line, this.reader.Column);
}
//case ':':// keep going
case ';':
{
// continue parsing rest of delcarations
goto ParseDeclarations;
}
case '}':
{
// no more declarations
return(ruleSet);
}
}
}
}
}
return(ruleSet);
}
/// <summary>
/// (BNF) declaration : property ':' S* value;
/// (BNF) property : IDENT S*;
/// </summary>
/// <returns></returns>
private CssDeclaration ParseDeclaration()
{
CssDeclaration declaration = new CssDeclaration();
char ch;
while (this.Read(out ch) && (Char.IsWhiteSpace(ch) || ch == ';'))
{
// skip whitespace, and empty declarations
}
// consume property name
switch (ch)
{
case '{':
case ':':
//case ';':
{
throw new SyntaxError("Declaration missing property name", this.reader.FilePath, this.reader.Line, this.reader.Column);
}
case '}':
{
// no more declarations
return null;
}
}
// read property, starting with current char
int start = this.Position;
while (this.Read(out ch) && !Char.IsWhiteSpace(ch) && ch != ':')
{
// consume property name
switch (ch)
{
case '{':
//case ':':
case ';':
{
throw new SyntaxError("Invalid CSS property name: " + this.Copy(start), this.reader.FilePath, this.reader.Line, this.reader.Column);
}
case '}':
{
this.PutBack();
goto case ';';
}
}
}
declaration.Property = this.Copy(start);
if (Char.IsWhiteSpace(ch))
{
while (this.Read(out ch) && (Char.IsWhiteSpace(ch)))
{
// skip whitespace
}
}
if (ch != ':')
{
// missing the property delim and value
if (ch == ';' || ch == '}')
{
// these are good chars for resyncing
// so put them back on the stream to
// not create subsequent errors
this.PutBack();
}
throw new SyntaxError("Expected <property> : <value>", this.reader.FilePath, this.reader.Line, this.reader.Column);
}
CssValueList value = this.ParseValue();
declaration.Value = value;
return declaration;
}