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README.md
dpy.q

README.md

dpy

General object display with type and structure

Displays an arbitrary q object, revealing its type, rank, and shape in a nested format.

Usage

Name and Syntax Description
dpy x Displays the specified object. dpy is defined in the global namespace

dpy uses standard Q type characters to represent type, with uppercase indicating a nonscalar value (e.g. a vector or higher-dimensional array). This set is augmented with the following additional type characters:

  • l, L: Scalar or array enumerated value
  • A: Keyed or unkeyed table
  • Y: Dictionary
  • #: Heterogeneous array
  • :: Function or operator

Examples

q)dpy 3 4
.---.
|3 4|
'J--'

q)dpy enlist 3 4
.-----.
|.---.|
||3 4||
|'J--'|
'#----'

q)dpy("yellow";1011000011b)
.------------.
|.------.    |
||yellow|    |
|'C-----'    |
|.----------.|
||1011000011||
|'B---------'|
'#-----------'

q)dpy enlist enlist "abc"
.-------.
|.-----.|
||.---.||
|||abc|||
||'C--'||
|'#----'|
'#------'

q)dpy dpy
.-------------------------.
|{-1 .dpy.trt .dpy.fmt x;}|
':------------------------'

q)dpy(((2 3 4;1011000011b);"howdy");2 3#3)
.----------------.
|.--------------.|
||.------------.||
|||.-----.     |||
||||2 3 4|     |||
|||'J----'     |||
|||.----------.|||
||||1011000011||||
|||'B---------'|||
||'#-----------'||
||.-----.       ||
|||howdy|       ||
||'C----'       ||
|'#-------------'|
|.-----.         |
||3 3 3|         |
||3 3 3|         |
|'J----'         |
'#---------------'

q)dpy parse"select event from tbl where t>0"
.--------------.
|.-.           |
||?|           |
|':'           |
|              |
|`tbl          |
|s             |
|.-------.     |
||.-----.|     |
|||.---.||     |
||||.-.|||     |
|||||>||||     |
||||':'|||     |
||||   |||     |
||||`t |||     |
||||s  |||     |
||||   |||     |
||||0  |||     |
||||j  |||     |
|||'#--'||     |
||'#----'|     |
|'#------'     |
|              |
|0             |
|b             |
|.------------.|
||event| event||
|'Y-----------'|
'#-------------'

Under Windows, the display would look different. (This won't be accurate unless you're viewing this page on a Windows machine, or have chosen an output encoding such as "Western (DOS Latin 1)". This encoding may not be in your default list.)

q)dpy 3 4
┌───┐
│3 4│
└J──┘

q)dpy enlist 3 4
┌─────┐
│┌───┐│
││3 4││
│└J──┘│
└#────┘

q)dpy("yellow";1011000011b)
┌────────────┐
│┌──────┐    │
││yellow│    │
│└C─────┘    │
│┌──────────┐│
││1011000011││
│└B─────────┘│
└#───────────┘

q)dpy enlist enlist "abc"
┌───────┐
│┌─────┐│
││┌───┐││
│││abc│││
││└C──┘││
│└#────┘│
└#──────┘

q)dpy dpy
┌─────────────────────────┐
│{-1 .dpy.trt .dpy.fmt x;}│
└:────────────────────────┘

q)dpy(((2 3 4;1011000011b);"howdy");2 3#3)
┌────────────────┐
│┌──────────────┐│
││┌────────────┐││
│││┌─────┐     │││
││││2 3 4│     │││
│││└J────┘     │││
│││┌──────────┐│││
││││1011000011││││
│││└B─────────┘│││
││└#───────────┘││
││┌─────┐       ││
│││howdy│       ││
││└C────┘       ││
│└#─────────────┘│
│┌─────┐         │
││3 3 3│         │
││3 3 3│         │
│└J────┘         │
└#───────────────┘

q)dpy parse"select event from tbl where t>0"
┌──────────────┐
│┌─┐           │
││?│           │
│└:┘           │
│              │
│`tbl          │
│s             │
│┌───────┐     │
││┌─────┐│     │
│││┌───┐││     │
││││┌─┐│││     │
│││││>││││     │
││││└:┘│││     │
││││   │││     │
││││`t │││     │
││││s  │││     │
││││   │││     │
││││0  │││     │
││││j  │││     │
│││└#──┘││     │
││└#────┘│     │
│└#──────┘     │
│              │
│0             │
│b             │
│┌────────────┐│
││event| event││
│└Y───────────┘│
└#─────────────┘

Higher-dimensional arrays are represented through leading axis indicators, with additional blank lines separating hyperplanes.

q)dpy 2 3 4#til 24
..-----------.
||0  1  2  3 |
||4  5  6  7 |
||8  9  10 11|
||           |
||12 13 14 15|
||16 17 18 19|
||20 21 22 23|
''J----------'

q)dpy 2 3 4 5#til 120
...-------------------.
|||0   1   2   3   4  |
|||5   6   7   8   9  |
|||10  11  12  13  14 |
|||15  16  17  18  19 |
|||                   |
|||20  21  22  23  24 |
|||25  26  27  28  29 |
|||30  31  32  33  34 |
|||35  36  37  38  39 |
|||                   |
|||40  41  42  43  44 |
|||45  46  47  48  49 |
|||50  51  52  53  54 |
|||55  56  57  58  59 |
|||                   |
|||                   |
|||60  61  62  63  64 |
|||65  66  67  68  69 |
|||70  71  72  73  74 |
|||75  76  77  78  79 |
|||                   |
|||80  81  82  83  84 |
|||85  86  87  88  89 |
|||90  91  92  93  94 |
|||95  96  97  98  99 |
|||                   |
|||100 101 102 103 104|
|||105 106 107 108 109|
|||110 111 112 113 114|
|||115 116 117 118 119|
'''J------------------'

An at-sign (@) on the top of an array indicates that the associated axis is empty.

q)dpy 0#0i
.@.
| |
'I'

q)dpy 2 1 0#0
..@.
|| |
|| |
|| |
''J'

On Windows, this would look as follows:

q)dpy 0#0i
┌@┐
│ │
└I┘

q)dpy 2 1 0#0
┌┌@┐
││ │
││ │
││ │
└└J┘

Configuration

The following functions can be used to control the displayed output:

Name and Syntax Description
.dpy.setc n Sets the corner and side box drawing characters. Use 0 for ASCII characters, 1 for Windows graphic characters, and 2 for post-processing via .dpy.trt (see the section entitled "Custom Output Translation" for additional information). The default is 1 under Windows and 0 otherwise
.dpy.trt x Defines arbitrary character translations to be applied to the output prior to display. This can, for example, be used to illustrate object nesting through colo[u]r; see below for details

dpy can be wired into the d namespace by adding the following lines to your q.q file:

\l dpy.q
.d.e:('[dpy;value])

Then, invoke from the Q command prompt via:

q)d)2 3#til 6
.-----.
|0 1 2|
|3 4 5|
'J----'

Custom Output Translation

You can use .dpy.trt to customize the output that is rendered to your display device. The following example shows how the box drawing characters can be displayed in a specific colour.

//
// Bash support for dpy to draw boxes in a configured colour.
//

\d .dpy

setc 2 / Enable character post-processing mode

PC:.dpy`tl`tr`bl`br`vl`vr`ht`hb / Placeholder output characters configured in <.dpy.setc>


//
// @desc Modifies  `.dpy.trt`'s default behaviour by replacing box drawing
// characters with semi-graphic character escape sequences.
//
// @param bc {string}	Specifies bash colour (see <bces> above).
// @param l {string}	Specifies a list of strings that will be remapped.
//
// @example:
// 	q)\l dpy.q
//	q).dpy.setc 2
//	q).dpy.trt:clrtrt["1;35";] / Light purple boxes
// 
clrtrt:{[bc;l]
    bbd:{bces[x] "\033(0",y,"\033(B"}[bc;] each "\154\153\155\152\170\170\161\161";
    rbdc[;bbd] each l
    }


//
// @desc Wraps a string with a Bash colour escape sequence.
//
// The following colours are supported:
//
//  0;30 - Black  0;31 - Red		1;30 - Dark Gray   1;31 - Light Red			     
//  0;34 - Blue	  0;35 - Purple		1;34 - Light Blue  1;35 - Light Purple 			    
//  0;32 - Green  0;33 - Brown		1;32 - Light Green 1;33 - Yellow	     
//  0;36 - Cyan	  0;37 - Light Gray	1;36 - Light Cyan  1;37 - White 	 
//
// @param bc {string}	Specifies bash colour.
// @param s {string}	Specifies string to wrap in colour esacpe sequence.
//
// @return {string}	The wrapped string.
//
bces:{[bc;s] "\033[",bc,"m",s,"\033[0m"} / Bash colour escape sequence


//
// @desc Replaces single-character box drawing characters with Unix semi-grpahic
// characters.
//
// @param s {string}	Specifies string to modify.
// @param bdc {string}	Specifies the table of escape sequences to draw semi-
//			graphic characters.
//
rbdc:{[s;bdc]
    j:where b|-1_1b,b:s in PC;
    t:j _ s;t[where b@j]:bdc[PC?s where b];(,/)t
    }


//
// Sample <clrtrt> projections.
//
redtrt:clrtrt["0;31";] / Make boxes red
cyantrt:clrtrt["1;36";] / Make boxes cyan

trt:cyantrt

\d .

As a variant, the next example shows how the box drawing characters can be augmented through the use of colour to reinforce nesting level visually.

//
// Bash support for dpy to reinforce nesting level through colour.
//

\d .dpy

setc 2 / Enable character post-processing mode

NC:("0;34";"0;36";"0;37";"0;31";"1;33";"1;32") / Change to suit preferences
PC:.dpy`tl`tr`bl`br`vl`vr`ht`hb / Placeholder output characters configured in <.dpy.setc>
EB:"\154\153\155\152\170\170\161\161" / Escaped box drawing characters


//
// @desc Modifies `.dpy.trt`'s default behaviour by replacing box drawing
// characters with semi-graphic escape sequences and colourizing each nesting
// level in a different colour.
//
// @param s {string}	String to modify.
//
// @example:
//	q)\l dpy.q
//	q).dpy.trt:.dpy.nsttrt each
// 
nsttrt:{[s]
    d:(sums s in "\332\263\300")-
        -1_0i,sums s in "\277\272\331"; / Determine nesting depth by looking for left and right characters

    j:where b|-1_1b,b:s in PC; 
    t:j _ s;
    t[where b@j]:{"\033[",(x`col),"m\033(0",(x`bdc),"\033(B\033[0m"} each 
        flip `col`bdc!(NC[mod[-1+d where b;count NC]];EB[PC?s where b]);

    (,/)t 	
    }

trt:nsttrt each

\d .

Credits

Thanks to Hugh Hyndman and Fadel Al-Jaifi of First Derivatives for the Bash output customization ideas and logic.

Author

Leslie Goldsmith, First Derivatives

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