253 lines
10 KiB
Factor
253 lines
10 KiB
Factor
USING: prettyprint.backend prettyprint.config prettyprint.custom
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prettyprint.sections help.markup help.syntax
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io kernel words definitions quotations strings generic classes
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prettyprint.private ;
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IN: prettyprint
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ARTICLE: "prettyprint-numbers" "Prettyprinting numbers"
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"The " { $link . } " word prints numbers in decimal. A set of words in the " { $vocab-link "prettyprint" } " vocabulary is provided to print integers using another base."
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{ $subsections
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.b
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.o
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.h
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} ;
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ARTICLE: "prettyprint-stacks" "Prettyprinting stacks"
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"Prettyprinting the current data, retain, call stacks:"
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{ $subsections
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.s
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.r
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.c
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}
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"Prettyprinting any stack:"
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{ $subsections stack. }
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"Prettyprinting any call stack:"
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{ $subsections callstack. }
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"Note that calls to " { $link .s } " can also be included inside words as a debugging aid, however a more convenient way to achieve this is to use the annotation facility. See " { $link "tools.annotations" } "." ;
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ARTICLE: "prettyprint-variables" "Prettyprint control variables"
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"The following variables affect the " { $link . } " and " { $link pprint } " words if set in the current dynamic scope:"
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{ $subsections
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tab-size
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margin
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nesting-limit
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length-limit
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line-limit
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number-base
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string-limit?
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boa-tuples?
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c-object-pointers?
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}
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"The default limits are meant to strike a balance between readability, and not producing too much output when large structures are given. There are two combinators that override the defaults:"
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{ $subsections with-short-limits without-limits }
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"That the " { $link short. } " and " { $link pprint-short } " words wrap calls to " { $link . } " and " { $link pprint } " in " { $link with-short-limits } ". Code that uses the prettyprinter for serialization should use " { $link without-limits } " to avoid producing unreadable output." ;
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ARTICLE: "prettyprint-limitations" "Prettyprinter limitations"
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"When using the prettyprinter as a serialization mechanism, keep the following points in mind:"
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{ $list
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{ "When printing words, " { $link POSTPONE: USING: } " declarations are only output if the " { $link pprint-use } " or " { $link unparse-use } " words are used." }
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{ "Long output will be truncated if certain " { $link "prettyprint-variables" } " are set." }
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"Shared structure is not reflected in the printed output; if the output is parsed back in, fresh objects are created for all literal denotations."
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{ "Circular structure is not printed in a readable way. For example, try this:"
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{ $code "{ f } dup dup set-first ." }
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}
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"Floating point numbers might not equal themselves after being printed and read, since a decimal representation of a float is inexact."
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}
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"On a final note, the " { $link short. } " and " { $link pprint-short } " words restrict the length and nesting of printed sequences, their output will very likely not be valid syntax. They are only intended for interactive use." ;
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ARTICLE: "prettyprint-section-protocol" "Prettyprinter section protocol"
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"Prettyprinter sections must subclass " { $link section } ", and they must also obey a protocol."
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$nl
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"Layout queries:"
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{ $subsections
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section-fits?
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indent-section?
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unindent-first-line?
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newline-after?
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short-section?
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}
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"Printing sections:"
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{ $subsections
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short-section
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long-section
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}
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"Utilities to use when implementing sections:"
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{ $subsections
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new-section
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new-block
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add-section
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} ;
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ARTICLE: "prettyprint-sections" "Prettyprinter sections"
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"The prettyprinter's formatting engine can be used directly:"
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{ $subsections with-pprint }
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"Code in a " { $link with-pprint } " block or a method on " { $link pprint* } " can build up a tree of " { $emphasis "sections" } ". A section is either a text node or a " { $emphasis "block" } " which itself consists of sections."
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$nl
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"Once the output sections have been generated, the tree of sections is traversed and intelligent decisions are made about indentation and line breaks. Finally, text is output."
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{ $subsections section }
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"Adding leaf sections:"
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{ $subsections
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line-break
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text
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styled-text
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}
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"Nesting and denesting sections:"
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{ $subsections
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<object
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<block
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<inset
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<flow
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<colon
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block>
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}
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"New types of sections can be defined."
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{ $subsections "prettyprint-section-protocol" } ;
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ARTICLE: "prettyprint-literal" "Literal prettyprinting protocol"
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"Most custom data types have a literal syntax which resembles a sequence. An easy way to define such a syntax is to add a method to the " { $link pprint* } " generic word which calls " { $link pprint-object } ", and then to provide methods on two other generic words:"
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{ $subsections
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pprint-delims
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>pprint-sequence
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}
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"For example, consider the following data type, together with a parsing word for creating literals:"
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{ $code
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"TUPLE: rect w h ;"
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""
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"SYNTAX: RECT["
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" scan-word"
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" scan-word \\ * assert="
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" scan-word"
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" scan-word \\ ] assert="
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" <rect> suffix! ;"
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}
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"An example literal might be:"
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{ $code "RECT[ 100 * 200 ]" }
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"Without further effort, the literal does not print in the same way:"
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{ $unchecked-example "RECT[ 100 * 200 ] ." "T{ rect f 100 200 }" }
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"However, we can define three methods easily enough:"
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{ $code
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"M: rect pprint-delims drop \\ RECT[ \\ ] ;"
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"M: rect >pprint-sequence dup rect-w \\ * rot rect-h 3array ;"
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"M: rect pprint* pprint-object ;"
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}
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"Now, it will be printed in a custom way:"
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{ $unchecked-example "RECT[ 100 * 200 ] ." "RECT[ 100 * 200 ]" } ;
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ARTICLE: "prettyprint-literal-more" "Prettyprinting more complex literals"
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"If the " { $link "prettyprint-literal" } " is insufficient, a method can be defined to control prettyprinting directly:"
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{ $subsections pprint* }
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"Some utilities which can be called from methods on " { $link pprint* } ":"
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{ $subsections
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pprint-object
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pprint-word
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pprint-elements
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pprint-string
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pprint-prefix
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}
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"Custom methods defined on " { $link pprint* } " do not perform I/O directly, instead they call prettyprinter words to construct " { $emphasis "sections" } " of output. See " { $link "prettyprint-sections" } "." ;
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ARTICLE: "prettyprint-extension" "Extending the prettyprinter"
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"One can define literal syntax for a new class using the " { $link "parser" } " together with corresponding prettyprinting methods which print instances of the class using this syntax."
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{ $subsections
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"prettyprint-literal"
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"prettyprint-literal-more"
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}
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"The prettyprinter actually exposes a general source code output engine and is not limited to printing object structure."
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{ $subsections "prettyprint-sections" } ;
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ARTICLE: "prettyprint" "The prettyprinter"
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"One of Factor's key features is the ability to print almost any object as a valid source literal expression. This greatly aids debugging and provides the building blocks for light-weight object serialization facilities."
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$nl
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"Prettyprinter words are found in the " { $vocab-link "prettyprint" } " vocabulary."
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$nl
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"The key words to print an object to " { $link output-stream } "; the first two emit a trailing newline, the second two do not:"
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{ $subsections
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.
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short.
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pprint
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pprint-short
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pprint-use
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}
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"The string representation of an object can be requested:"
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{ $subsections
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unparse
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unparse-use
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}
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"Utility for tabular output:"
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{ $subsections pprint-cell }
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"More prettyprinter usage:"
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{ $subsections
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"prettyprint-numbers"
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"prettyprint-stacks"
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}
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"Prettyprinter customization:"
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{ $subsections
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"prettyprint-variables"
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"prettyprint-extension"
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"prettyprint-limitations"
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}
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{ $see-also "number-strings" "see" } ;
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ABOUT: "prettyprint"
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HELP: pprint
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{ $values { "obj" object } }
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{ $description "Prettyprints an object to " { $link output-stream } ". Output is influenced by many variables; see " { $link "prettyprint-variables" } "." }
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{ $warning
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"Unparsing a large object can take a long time and consume a lot of memory. If you need to print large objects, use " { $link pprint-short } " or set some " { $link "prettyprint-variables" } " to limit output size."
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} ;
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{ pprint pprint* with-pprint } related-words
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HELP: .
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{ $values { "obj" object } }
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{ $description "Prettyprints an object to " { $link output-stream } " with a trailing line break. Output is influenced by many variables; see " { $link "prettyprint-variables" } "." }
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{ $warning
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"Printing a large object can take a long time and consume a lot of memory. If you need to print large objects, use " { $link short. } " or set some " { $link "prettyprint-variables" } " to limit output size."
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} ;
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HELP: unparse
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{ $values { "obj" object } { "str" "Factor source string" } }
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{ $description "Outputs a prettyprinted string representation of an object. Output is influenced by many variables; see " { $link "prettyprint-variables" } "." }
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{ $warning
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"Unparsing a large object can take a long time and consume a lot of memory. If you need to unparse large objects, use " { $link unparse-short } " or set some " { $link "prettyprint-variables" } " to limit output size."
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} ;
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HELP: pprint-short
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{ $values { "obj" object } }
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{ $description "Prettyprints an object to " { $link output-stream } ". This word rebinds printer control variables to enforce “shorter” output. See " { $link "prettyprint-variables" } "." } ;
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HELP: short.
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{ $values { "obj" object } }
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{ $description "Prettyprints an object to " { $link output-stream } " with a trailing line break. This word rebinds printer control variables to enforce “shorter” output." } ;
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HELP: .b
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{ $values { "n" "an integer" } }
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{ $description "Outputs an integer in binary." } ;
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HELP: .o
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{ $values { "n" "an integer" } }
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{ $description "Outputs an integer in octal." } ;
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HELP: .h
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{ $values { "n" "an integer or floating-point value" } }
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{ $description "Outputs an integer or floating-point value in hexadecimal." } ;
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HELP: stack.
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{ $values { "seq" "a sequence" } }
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{ $description "Prints a the elements of the sequence, one per line." }
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{ $notes "This word is used in the implementation of " { $link .s } " and " { $link .r } "." } ;
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HELP: callstack.
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{ $values { "callstack" callstack } }
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{ $description "Displays a sequence output by " { $link callstack } " in a nice way, by highlighting the current execution point in every call frame with " { $link -> } "." } ;
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HELP: .c
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{ $description "Displays the contents of the call stack, with the top of the stack printed first." } ;
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HELP: .r
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{ $description "Displays the contents of the retain stack, with the top of the stack printed first." } ;
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HELP: .s
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{ $description "Displays the contents of the data stack, with the top of the stack printed first." } ;
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