Miscellaneous Functions

The markup algebra includes several miscellaneous functions for converting between different value types, for example turning a string into a page and back, accessing the begin and end tags of a piece (See See Miscellaneous Functions). To give a feeling for how these functions are used, we first define a new page containing a heading and 2-by-2 table:

var P = NewPage("<html><body>

<table>

<tr>

</tr>

<tr>

</tr>

</table>

</body></html>", "text/html");

Note that the second argument to NewPage defines the parser to be used to parse the string into a page. For the definition above, the following WebL expressions evaluate in the following manner:

Markup(P) // Returns "<html><body> ...

// ... </html>" as above.

var H = Elem(P, "h1")[0] // Returns the first H1.

Markup(H) // Returns "<h1>Test Page</h1>."

Text(P) // Returns "Test Page A 100 B 230"

// (including white space).

Text(H) // Returns "Test Page".

Name(H) // Returns "h1".

var T = Elem(P, "td") // Returns all the TD elements.

Markup(T[0]) // Returns

// "<td align="center">A</td>".

Markup(T[1]) // Returns "<td>100</td>".

Text(T[0]) // Returns "A".

Text(T[1]) // Returns "100".

Name(T[0]) // Returns "td".

T[0].align // Returns "center".

var x = BeginTag(H), y = EndTag(H);

Page(H) == P // Returns true.

Page(x) == P // Returns true.

Page(y) == P // Returns true

The Pretty function is similar to the Markup function except that it pretty-prints the markup by indenting elements according to their nesting level. This is useful to study the structure of badly formatted HTML and XML pages. Note that pretty-printing a page involves a reformatting of white spaces and new lines, so the resulting string might differ dramatically from the original page source (sometimes enough to break scripts that worked correctly on the "ugly" page)1.

Miscellaneous Functions
Function	Description
BeginTag(q: piece): tag	Returns the begin tag of a piece.
EndTag(q: piece): tag	Returns the end tag of a piece.
ExpandCharEntities(p: page, s: string): string	Expands the character entities (eg. <, &) in s to their Unicode character equivalents. The DTD of page p is used for the lookups.
ExpandCharEntities(s: string): string	Expands the character entities (eg. <, &) in s to their Unicode character equivalents. The HTML 4.0 DTD is used for the lookups.
Markup(p: page): string	Turns a page object back into a string.
Markup(q: piece): string	Turns a piece object back into a string.
Name(q: piece): string	Returns the name of a piece, or the empty string in the case of q being unnamed.
NewPage(s: string, mimetype: string): page	Parses the string s with the mimetype indicated markup parser and returns a page object.
NewPiece(s: string, mimetype: string): piece	Equivalent to Content(NewPage(s, mimetype)).
NewPieceSet(s: set): pieceset	Converts a set of pieces into a piece set. Thows an EmptySet exception should s be empty.
NewPieceSet(p: page): pieceset	Returns an empty pieceset associated with with page p.
Page(q: piece): page	Returns the page a piece belongs to.
Page(t: tag): page	Returns the page a tag belongs to.
Pretty(p: page): string	Returns a pretty-printed version of the page.
Pretty(q: piece): string	Returns a pretty-printed version of a piece.
Size(p: pieceset):int	Returns the number of pieces belonging to p.
Text(p: page): string	Returns the text (sans tags) of a page.
Text(q: piece): string	Returns the text (sans tags) of a piece.

1. WebL tries to ensure that the pretty-printed page still renders in the browser in the same manner as the original page by using some limited inbuilt knowledge about markup. For example, HTML preformatted elements (PRE) are not changed.

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