---
name: "PDL::Doc::Perldl"
section: "3pm"
platform: "linux"
package: "pdl"
version: "1:2.100-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/PDL::Doc::Perldl"
---

# PDL::Doc::Perldl(3pm)

commands for accessing PDL doc database from 'perldl' shell

## NAME

PDL::Doc::Perldl - commands for accessing PDL doc database from 'perldl' shell

## DESCRIPTION

This module provides a set of functions to access the PDL documentation database, for use from the *perldl* shell as well as the *pdldoc* command-line program.

Autoload files are also matched, via a search of the PDLLIB autoloader tree.  That behavior can be switched off with the variable  `$PERLDL::STRICT_DOCS` (true: don't search autoload tree; false: search the autoload tree.)

In the interest of brevity, functions that print module names (at the moment just "apropos" and "usage") use some shorthand notation for module names. Currently-implemented shorthands are

- •

  P:: (short for PDL::)

- •

  P::G:: (short for PDL::Graphics::)

To turn this feature off, set the variable `$PERLDL::long_mod_names` to a true value. The feature is assumed to be on for the purposes of this documentation.

## SYNOPSIS

```
 use PDL::Doc::Perldl; # Load all documentation functions
```

## FUNCTIONS

### apropos

Regex search PDL documentation database

```
 apropos 'text'
```

```
 pdl> apropos 'pic'
 PDL::IO::Pic    P::IO::Pic  Module: image I/O for PDL
 grabpic3d       P::G::TriD  Grab a 3D image from the screen.
 rim             P::IO::Pic  Read images in most formats, with improved RGB handling.
 rpic            P::IO::Pic  Read images in many formats with automatic format detection.
 rpiccan         P::IO::Pic  Test which image formats can be read/written
 wim             P::IO::Pic  Write a pdl to an image file with selected type (or using filename extensions)
 wmpeg           P::IO::Pic  Write an image sequence (a (3,x,y,n) byte pdl) as an animation.
 wpic            P::IO::Pic  Write images in many formats with automatic format selection.
 wpiccan         P::IO::Pic  Test which image formats can be read/written
```

To find all the manuals that come with PDL, try

```
  apropos 'manual:'
```

and to get quick info about PDL modules say

```
  apropos 'module:'
```

You get more detailed info about a PDL function/module/manual with the `"help"` function

### PDL::Doc::Perldl::search\_docs

Internal routine to search docs database and autoload files

### PDL::Doc::Perldl::finddoc

Internal interface to the PDL documentation searcher

### find\_autodoc

Internal routine that finds and returns documentation in the PDL::AutoLoader path, if it exists.

You feed in a topic and it searches for the file "${topic}.pdl".  If that exists, then the filename gets returned in a match structure appropriate for the rest of finddoc.

### usage

Prints usage information for a PDL function

```
 Usage: usage 'func'
```

```
   pdl> usage 'inner'
   inner           P::Primitive  Inner product over one dimension
   Signature: inner(a(n); b(n); [o]c())
```

### sig

prints signature of PDL function

```
 sig 'func'
```

The signature is the normal dimensionality of the function's arguments.  Calling with different dimensions doesn't break -- it causes broadcasting.  See PDL::PP and PDL::Broadcasting for details.

```
  pdl> sig 'outer'
    Signature: outer(a(n); b(m); [o]c(n,m))
```

### whatis

Describe a perl and/or PDL variable or expression.  Useful for determining the type of an expression, identifying the keys in a hash or a data structure, or examining WTF an unknown object is.

```
 Usage: whatis $var
        whatis <expression>
```

### help

print documentation about a PDL function or module or show a PDL manual

In the case of multiple matches, the first command found is printed out, and the remaining commands listed, along with the names of their modules.

```
 Usage: help 'func'
```

```
 pdl> help 'PDL::Tutorials' # show the guide to PDL tutorials
 pdl> help 'PDL::Slices'    # show the docs in the PDL::Slices module
 pdl> help 'slice'          # show docs on the 'slice' function
```

### badinfo

provides information on the bad-value support of a function

And has a horrible name.

```
 badinfo 'func'
```

```
  pdl> badinfo 'inner'
  Bad value support for inner (in module PDL::Primitive)
      If "a() * b()" contains only bad data, "c()" is set bad. Otherwise "c()"
      will have its bad flag cleared, as it will not contain any bad values.
```