Sysquake Pro – Table of Contents

Sysquake for LaTeX – Table of Contents

# Help Functions

### help

Help about an LME function.

#### Syntax

help functionname help 'operator' help help(str, fd=fd) b = help(str)

#### Description

`help functionname` displays a help message about
function whose name is `functionname`. `help 'operator'`
displays a help message about an operator. For methods (functions for arguments
of a specific class), the class should be specified as `class::method`,
except for constructors where both `class` and `class::class`
are recognized. Without argument, `help`
displays a message about the help command itself.

For user functions, `help` uses the first comment which immediately
follows the function header. The comment may be a continuous set of lines
beginning with `%` or `//`, or a single block of
lines delimited with `/*` and `*/`. Lines which
contain `/*` and `*/` cannot have any other
character, not even spaces. Alternatively for
user functions, or for built-in or extension functions, the help text is
found in files with suffix ".hlp" in the same folders as libraries.
For functions unknown to LME (such as functions defined in libraries which
have not been loaded with `use`), `help` searches
in file `other.hlp`, which typically includes each library
`hlp` files with `includeifexists` statements.

If no matching function is found, `help` has the same effect as
`lookfor`, i.e. it proposes a list of functions whose short
description contains the string passed as argument (or just the method
name if the argument has the syntax `class::method`).

A named argument `fd` can specify the output channel; in that case,
the command syntax cannot be used.

With an output argument, `help` returns `true` if
help is found for its input argument, `false` otherwise. Help is
not displayed. The `lookfor` fallback is not attempted.

#### Examples

Help about function `sin`:

help sin Sine. SYNTAX y = sin(x) ...

Help about operator `+`:

help '+' Addition. SYNTAX x + y M1 + M2 ...

Source code of function `dctmtx` with its help comment block:

function T = dctmtx(n) /* Discrete cosine transform matrix. SYNTAX T = dctmtx(n) DESCRIPTION dctmtx(n) returns an n-by-n square matrix T such that Y=T*y is the discrete cosine transform of the columns ... */ T = [repmat(1/sqrt(n),1,n); ... sqrt(2/n)*cos(pi/(2*n)*repmat(1:2:2*n,n-1,1)... .*repmat((1:n-1)',1,n))];

#### See also

### lookfor

Search functions.

#### Syntax

lookfor str lookfor('str') lookfor('str', fd=fd)

#### Description

`lookfor str` searches the characters `str`
in the short description of all commands and functions and displays
all the matches. Case is ignored. If `str` contains spaces or non-alphanumeric
characters, the syntax `lookfor('str')` must be used.

A named argument `fd` can specify the output channel; in that case,
the command syntax cannot be used.

#### Example

lookfor arc lookfor Search functions. acos Arc cosine. asin Arc sine. atan Arc tangent.