The Language Pec

This document was automatically generated by the BNF-Converter. It was generated together with the lexer, the parser, and the abstract syntax module, which guarantees that the document matches with the implementation of the language (provided no hand-hacking has taken place).

The lexical structure of Pec

Literals

String literals String have the form "x", where x is any sequence of any characters except " unless preceded by \.

Character literals Char have the form 'c', where c is any single character.

Frac literals are recognized by the regular expression `'-'? digit+ '.' digit+ ('e' '-'? digit+)?`

Uident literals are recognized by the regular expression `upper (letter | digit | '_')*`

Lident literals are recognized by the regular expression `(lower | '_') (letter | digit | '_')*`

USym literals are recognized by the regular expression `('!' | '#' | '$' | '%' | '&' | '*' | '+' | '-' | '.' | '/' | ':' | '<' | '=' | '>' | '?' | '@' | '\' | '^' | '|' | '~')+`

Number literals are recognized by the regular expression `'-'? digit+`

Count literals are recognized by the regular expression `'#' digit+`

Reserved words and symbols

The set of reserved words is the set of terminals appearing in the grammar. Those reserved words that consist of non-letter characters are called symbols, and they are treated in a different way from those that are similar to identifiers. The lexer follows rules familiar from languages like Haskell, C, and Java, including longest match and spacing conventions.

The reserved words used in Pec are the following:

The symbols used in Pec are the following:

Comments

Single-line comments begin with //.Multiple-line comments are enclosed with /* and */.

The syntactic structure of Pec

Non-terminals are enclosed between < and >. The symbols -> (production), | (union) and eps (empty rule) belong to the BNF notation. All other symbols are terminals.