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Reference Manual of the Scheme Pretty Printing Library

Kurt NÝrmark © normark@cs.aau.dk Department of Computer Science, Aalborg University, Denmark.

LAML Source file: lib/scheme-pretty-printing.scm

This is a Lisp pretty printing library, which especially is oriented towards Scheme.

The pretty printer handles all aspects of Scheme which has special lexical syntax: lists, pairs (dot notation), booleans, chars, vectors, and quasi quotation (backquoting). In addition, the pretty printing function handles Scheme special forms such as cond, let, define, if, etc.

A few parameters (global variables) control the pretty printer.

Conventional comments, read by the this pretty printer, are lost. This library assumes that comments are represented as syntactical forms like (comment!!! n "A comment"). The LAML schemedoc tool contains a procedure lexical-to-syntactical-comments! which converts conventional, semicolon Lisp comments to the syntactical comments expected by the pretty printing library. The variable syntactical-comment-symbol (and the variable COMMENT-FORM-START in SchemeDoc) allows you to control the prefix symbol of syntactical comments.

The important top level functions of this library are pretty-print-lisp-file and pretty-print-lisp-form.

Internally, the pretty printer adds pretty-print tokens (strings or chars) to a list, which finally is reversed and linearized into a string.

This library relies on the general library (not loaded by this library).

In the laml.scm file there are LAML procedures scheme-pp and scheme-pp-simple which pretty print Scheme and Lisp files. pp-scheme handles comments properly. These are the most top-level Scheme pretty printing procedures in the LAML system.

Table of Contents:
1. Pretty printing parameters. 2. Top level pretty printing functions.

Alphabetic index:
indentation-delta indentation-delta An integer which gives the level of indentation
prefered-maximum-width prefered-maximum-width An integer that expresses the preferred maximum column width
pretty-print-lisp-file (pretty-print-lisp-file in-file-path [out-file-path]) Assume that in-file-path contains a lisp file with one or lisp forms.
pretty-print-lisp-form (pretty-print-lisp-form form) Pretty print form and return the pretty printed string
pretty-print-lisp-string (pretty-print-lisp-string str) Pretty print the string str and the return pretty printed string.
syntactical-comment-symbol syntactical-comment-symbol The symbol which is used for syntactical comments, such as (comment 2 "This is a comment").
use-single-lining use-single-lining A boolean which controls the application of single line pretty printing.


1 Pretty printing parameters.
The variables in this section controls the pretty printing.

indentation-delta
Form indentation-delta
Description An integer which gives the level of indentation
See also Scheme source file indentation-delta

use-single-lining
Form use-single-lining
Description A boolean which controls the application of single line pretty printing. If true, the Lisp pretty printer will pretty print short list forms on a single line
See also Scheme source file use-single-lining

prefered-maximum-width
Form prefered-maximum-width
Description An integer that expresses the preferred maximum column width
See also Scheme source file prefered-maximum-width

syntactical-comment-symbol
Form syntactical-comment-symbol
Description The symbol which is used for syntactical comments, such as (comment 2 "This is a comment"). It is recommended to use a symbol which is unlikely to be used in 'normal programs', such as comment!!!
See also Scheme source file syntactical-comment-symbol


2 Top level pretty printing functions.
In this section you will find the important, overall pretty printing functions.

pretty-print-lisp-file
Form (pretty-print-lisp-file in-file-path [out-file-path])
Description Assume that in-file-path contains a lisp file with one or lisp forms. Pretty prints the Lisp forms taken from in-file-path. Output them on the optional out-file-path (which per default is in-file-path).
Important warning: If only one file is given as parameter, the input file is overwritten by the pretty printed result.
See also Scheme source file pretty-print-lisp-file

pretty-print-lisp-form
Form (pretty-print-lisp-form form)
Description Pretty print form and return the pretty printed string
See also Scheme source file pretty-print-lisp-form

pretty-print-lisp-string
Form (pretty-print-lisp-string str)
Description Pretty print the string str and the return pretty printed string. This function is not efficient, because it generates a temporary file, from which we parse the string, and after this the function pretty-print-lisp-form is used.
See also Scheme source file pretty-print-lisp-string

Generated: Monday, November 14, 2011, 09:18:14
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