clojure.pprint

完整名称空间名称：clojure.pprint

概述

A Pretty Printer for Clojure

clojure.pprint implements a flexible system for printing structured data
in a pleasing, easy-to-understand format. Basic use of the pretty printer is 
simple, just call pprint instead of println. More advanced users can use 
the building blocks provided to create custom output formats. 

Out of the box, pprint supports a simple structured format for basic data 
and a specialized format for Clojure source code. More advanced formats, 
including formats that don't look like Clojure data at all like XML and 
JSON, can be rendered by creating custom dispatch functions. 

In addition to the pprint function, this module contains cl-format, a text 
formatting function which is fully compatible with the format function in 
Common Lisp. Because pretty printing directives are directly integrated with
cl-format, it supports very concise custom dispatch. It also provides
a more powerful alternative to Clojure's standard format function.

See documentation for pprint and cl-format for more information or 
complete documentation on the the clojure web site on github.

在Clojure版本1.2中添加

一种兼容Lisp的通用格式函数

公共变量和函数

*print-base*动态变量

The base to use for printing integers and rationals.

在Clojure版本1.2中添加

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*print-miser-width*2A动态变量

The column at which to enter miser style. Depending on the dispatch table, 
miser style add newlines in more places to try to keep lines short allowing for further 
levels of nesting.

在Clojure版本1.2中添加

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*print-pprint-dispatch*动态多方法

No usage documentation available

The pretty print dispatch function. Use with-pprint-dispatch or set-pprint-dispatch
to modify.

在Clojure版本1.2中添加

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*print-pretty*动态变量

Bind to true if you want write to use pretty printing

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*print-radix*动态变量

Print a radix specifier in front of integers and rationals. If *print-base* is 2, 8, 
or 16, then the radix specifier used is #b, #o, or #x, respectively. Otherwise the 
radix specifier is in the form #XXr where XX is the decimal value of *print-base* 

在Clojure版本1.2中添加

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*print-right-margin*动态变量

Pretty printing will try to avoid anything going beyond this column.
Set it to nil to have pprint let the line be arbitrarily long. This will ignore all 
non-mandatory newlines.

在Clojure版本1.2中添加

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*print-suppress-namespaces*动态变量

Don't print namespaces with symbols. This is particularly useful when 
pretty printing the results of macro expansions

在Clojure版本1.2中添加

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Cl-format函数

Usage: (cl-format writer format-in & args)

An implementation of a Common Lisp compatible format function. cl-format formats its
arguments to an output stream or string based on the format control string given. It 
supports sophisticated formatting of structured data.

Writer is an instance of java.io.Writer, true to output to *out* or nil to output 
to a string, format-in is the format control string and the remaining arguments 
are the data to be formatted.

The format control string is a string to be output with embedded 'format directives' 
describing how to format the various arguments passed in.

If writer is nil, cl-format returns the formatted result string. Otherwise, cl-format 
returns nil.

For example:
 (let [results [46 38 22]]
        (cl-format true "There ~[are~;is~:;are~]~:* ~d result~:p: ~{~d~^, ~}~%" 
                   (count results) results))

Prints to *out*:
 There are 3 results: 46, 38, 22

Detailed documentation on format control strings is available in the "Common Lisp the 
Language, 2nd edition", Chapter 22 (available online at:
http://www.cs.cmu.edu/afs/cs.cmu.edu/project/ai-repository/ai/html/cltl/clm/node200.html#SECTION002633000000000000000) 
and in the Common Lisp HyperSpec at 
http://www.lispworks.com/documentation/HyperSpec/Body/22_c.htm

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代码调度多方法

Usage: (code-dispatch object)

The pretty print dispatch function for pretty printing Clojure code.

在Clojure版本1.2中添加

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formattermacro

Usage: (formatter format-in)

Makes a function which can directly run format-in. The function is
fn [stream & args] ... and returns nil unless the stream is nil (meaning 
output to a string) in which case it returns the resulting string.

format-in can be either a control string or a previously compiled format.

在Clojure版本1.2中添加

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formatter-outmacro

Usage: (formatter-out format-in)

Makes a function which can directly run format-in. The function is
fn [& args] ... and returns nil. This version of the formatter macro is
designed to be used with *out* set to an appropriate Writer. In particular,
this is meant to be used as part of a pretty printer dispatch method.

format-in can be either a control string or a previously compiled format.

在Clojure版本1.2中添加

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fresh-line函数

Usage: (fresh-line)

Make a newline if *out* is not already at the beginning of the line. If *out* is
not a pretty writer (which keeps track of columns), this function always outputs a newline.

在Clojure版本1.2中添加

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get-pretty-writer函数

Usage: (get-pretty-writer writer)

Returns the java.io.Writer passed in wrapped in a pretty writer proxy, unless it's 
already a pretty writer. Generally, it is unnecessary to call this function, since pprint,
write, and cl-format all call it if they need to. However if you want the state to be 
preserved across calls, you will want to wrap them with this. 

For example, when you want to generate column-aware output with multiple calls to cl-format, 
do it like in this example:

    (defn print-table [aseq column-width]
      (binding [*out* (get-pretty-writer *out*)]
        (doseq [row aseq]
          (doseq [col row]
            (cl-format true "~4D~7,vT" col column-width))
          (prn))))

Now when you run:

    user> (print-table (map #(vector % (* % %) (* % % %)) (range 1 11)) 8)

It prints a table of squares and cubes for the numbers from 1 to 10:

       1      1       1    
       2      4       8    
       3      9      27    
       4     16      64    
       5     25     125    
       6     36     216    
       7     49     343    
       8     64     512    
       9     81     729    
      10    100    1000

在Clojure版本1.2中添加

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ppmacro

Usage: (pp)

A convenience macro that pretty prints the last thing output. This is
exactly equivalent to (pprint *1).

在Clojure版本1.2中添加

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pprintfunction

Usage: (pprint object)
       (pprint object writer)

Pretty print object to the optional output writer. If the writer is not provided, 
print the object to the currently bound value of *out*.

在Clojure版本1.2中添加

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pprint-indent函数

Usage: (pprint-indent relative-to n)

Create an indent at this point in the pretty printing stream. This defines how 
following lines are indented. relative-to can be either :block or :current depending 
whether the indent should be computed relative to the start of the logical block or
the current column position. n is an offset. 

This function is intended for use when writing custom dispatch functions.

Output is sent to *out* which must be a pretty printing writer.

在Clojure版本1.2中添加

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pprint-logical-block宏

Usage: (pprint-logical-block options* body)

Execute the body as a pretty printing logical block with output to *out* which 
must be a pretty printing writer. When used from pprint or cl-format, this can be 
assumed. 

This function is intended for use when writing custom dispatch functions.

Before the body, the caller can optionally specify options: :prefix, :per-line-prefix, 
and :suffix.

在Clojure版本1.2中添加

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pprint-newline函数

Usage: (pprint-newline kind)

Print a conditional newline to a pretty printing stream. kind specifies if the 
newline is :linear, :miser, :fill, or :mandatory. 

This function is intended for use when writing custom dispatch functions.

Output is sent to *out* which must be a pretty printing writer.

在Clojure版本1.2中添加

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pprint-tab函数

Usage: (pprint-tab kind colnum colinc)

Tab at this point in the pretty printing stream. kind specifies whether the tab
is :line, :section, :line-relative, or :section-relative. 

Colnum and colinc specify the target column and the increment to move the target
forward if the output is already past the original target.

This function is intended for use when writing custom dispatch functions.

Output is sent to *out* which must be a pretty printing writer.

THIS FUNCTION IS NOT YET IMPLEMENTED.

在Clojure版本1.2中添加

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print-length-loop宏

Usage: (print-length-loop bindings & body)

A version of loop that iterates at most *print-length* times. This is designed 
for use in pretty-printer dispatch functions.

在Clojure版本1.3中添加

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print-table函数

Usage: (print-table ks rows)
       (print-table rows)

Prints a collection of maps in a textual table. Prints table headings
ks, and then a line of output for each row, corresponding to the keys
in ks. If ks are not specified, use the keys of the first item in rows.

在Clojure版本1.3中添加

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SET-pprint-Dispatch函数

Usage: (set-pprint-dispatch function)

Set the pretty print dispatch function to a function matching (fn [obj] ...)
where obj is the object to pretty print. That function will be called with *out* set
to a pretty printing writer to which it should do its printing.

For example functions, see simple-dispatch and code-dispatch in 
clojure.pprint.dispatch.clj.

在Clojure版本1.2中添加

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简单调度多方法

Usage: (simple-dispatch object)

The pretty print dispatch function for simple data structure format.

在Clojure版本1.2中添加

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with-pprint-dispatch宏

Usage: (with-pprint-dispatch function & body)

Execute body with the pretty print dispatch function bound to function.

在Clojure版本1.2中添加

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写函数

Usage: (write object & kw-args)

Write an object subject to the current bindings of the printer control variables.
Use the kw-args argument to override individual variables for this call (and any 
recursive calls). Returns the string result if :stream is nil or nil otherwise.

The following keyword arguments can be passed with values:
  Keyword              Meaning                              Default value
  :stream              Writer for output or nil             true (indicates *out*)
  :base                Base to use for writing rationals    Current value of *print-base*
  :circle*             If true, mark circular structures    Current value of *print-circle*
  :length              Maximum elements to show in sublists Current value of *print-length*
  :level               Maximum depth                        Current value of *print-level*
  :lines*              Maximum lines of output              Current value of *print-lines*
  :miser-width         Width to enter miser mode            Current value of *print-miser-width*
  :dispatch            The pretty print dispatch function   Current value of *print-pprint-dispatch*
  :pretty              If true, do pretty printing          Current value of *print-pretty*
  :radix               If true, prepend a radix specifier   Current value of *print-radix*
  :readably*           If true, print readably              Current value of *print-readably*
  :right-margin        The column for the right margin      Current value of *print-right-margin*
  :suppress-namespaces If true, no namespaces in symbols    Current value of *print-suppress-namespaces*

  * = not yet supported

在Clojure版本1.2中添加

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write-out函数

Usage: (write-out object)

Write an object to *out* subject to the current bindings of the printer control 
variables. Use the kw-args argument to override individual variables for this call (and 
any recursive calls).

*out* must be a PrettyWriter if pretty printing is enabled. This is the responsibility
of the caller.

This method is primarily intended for use by pretty print dispatch functions that 
already know that the pretty printer will have set up their environment appropriately.
Normal library clients should use the standard "write" interface. 

在Clojure版本1.2中添加

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