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General Purpose PostScript Generating Utility

7.6.5 Syntax for the P-Rules

See section 7.5.5 P-Rules, for the definition of P-rule.

Because of various short cuts, there are many ways to declare a rule:

rules ::= rule_1 `,' rule_2... rule ::= `(' lhs rhs `)' | lhs srhs ; lhs ::= string | regex ; rhs ::= srhs `,' ... srhs ::= latex-keyword | expansion face expansion ::= string | `\'num | <nothing>; face ::= face-keyword | <nothing>;

The rules are the following:

• If the left-hand side (lhs) is a regular expression, then it is compiled with the following syntax bits:

  #define RE_SYNTAX_A2PS \ (/* Allow char classes. */ \ RE_CHAR_CLASSES \ /* Be picky. */ \ | RE_CONTEXT_INVALID_OPS \ /* Allow intervals with `{' and `}', forbid invalid ranges. */\ | RE_INTERVALS | RE_NO_BK_BRACES | RE_NO_EMPTY_RANGES \ /* `(' and `)' are the grouping operators. */ \ | RE_NO_BK_PARENS \ /* `|' is the alternation. */ \ | RE_NO_BK_VBAR)

  Basically it means that all of the possible operators are used, and that they are in non-backslashed form. For instance `(' and `)' stand for the group operator, while `\\(' stands for the character `('. See section `Regular Expression Syntax' in Regex manual, for a detailed description of the regular expressions.

• If no expansion is specified, then the matched string is used. For instance `(/fo*/, NULL, Keyword)' applied on the source `fooooo' produces `fooooo' in Keyword.

• If no face is given, then
  • if the context defines the default face, then this face is used;

  • if no default face is given, PLAIN is used.