help queries and displays help pages in the Scilab help browser

## Syntax

                help
                help(key)

## Arguments

key

  character string: The requested help page or pattern.

## Description

help opens the last displayed page.

help key searches for the `key` in the table of known key ids.

- If the key is known: opens the corresponding page. Exact keys are case-sensitive: For instance, `help type` and `help Type` open two different pages.

- Otherwise: calls `apropos(key)` that lists all pages including the given case-insensitive `key`, and opens the first page listed. The listed pages are ranked according to the frequency of the key occurrences in the page. The list entries are sorted by decreasing rank.

  In the `key`, any space or "|" character is considered as a sub-key separator. Each page including at least one subkey matches the query. For instance, `help "linear sparse"` will list all pages including any of the "linear" or "sparse" terms. Pages including both terms are at the top of the list.

A preferences option can be activated by Scilab's newcomers coming from Octave or Matlab languages, in the `General => Help and demos` preferences pannel:

                    preferences

If the Redirect Matlab terms to closest Scilab equivalent option is checked, then help queries matching no Scilab reserved keyword but matching a known Matlab/Octave item are automatically redirected to the equivalent Scilab feature and page.

### Menus

Language : | chooses the language of the displayed pages and left summary tree, among main supported ones. The current page is immediately updated for the chosen language. The chosen language is recorded for any forthcoming usage of the browser. The language used for the menus labels of the help browser is not changed.
Online : | See this page online: Tries to open the web browser and targets the current page on the https://help.scilab.org web site, for the current Scilab version and the current help language. A working internet connection is required. If the current page is from an external module or is a summary page, the action is impossible and canceled, and a warning messagebox is displayed.
Issues : | Tries to open the web browser, and searches on the https://gitlab.com/scilab/scilab/-/issues web site reports of issues declared about the item of the current page. A working internet connection is required. If the current page is from an external module or is a summary page, the action is impossible and canceled, and a warning messagebox is displayed.

### Contextual menu

### Other interactive features

The focus is on the displayed page:

CTRL F : | open a search field (inside the page) at the bottom of the browser.
CTRL mouse wheel : | Zoom in/out the page's content.
CTRL + : | Zoom in
CTRL - : | Zoom out
CTRL W : | closes the browser

close help closes the help browser.

See man for more explanation on how to write new help pages .

## Examples

    help
    help type
    help Type
    help plot3d
    help 6.1.1  // lists all pages whose history shows 6.1.1
    help "linear sparse"

## See also

- apropos
- head_comments
- Scilab documentation format

## History

6.1.1

- Language, Online and Issues menus and features added.
- The languages used for the help browser and for the session are now independent.
- "Redirect Matlab terms to the closest Scilab equivalent" feature implemented on Preferences.
- Loading an ATOMS module and its documentation no longer requires reopening the help browser to access it.
- `close help` implemented.