search history: >vim
			call histdel("/", '^\*')
<
		The following three are equivalent: >vim
			call histdel("search", histnr("search"))
			call histdel("search", -1)
			call histdel("search", '^' .. histget("search", -1) .. '$')
<
		To delete the last search pattern and use the last-but-one for
		the "n" command and 'hlsearch': >vim
			call histdel("search", -1)
			let @/ = histget("search", -1)
<

                Parameters: ~
                  • {history} (`string`)
                  • {item} (`any?`)

                Return: ~
                  (`0|1`)

histget({history} [, {index}])                                       *histget()*
		The result is a String, the entry with Number {index} from
		{history}.  See |hist-names| for the possible values of
		{history}, and |:history-indexing| for {index}.  If there is
		no such entry, an empty String is returned.  When {index} is
		omitted, the most recent item from the history is used.

		Examples:
		Redo the second last search from history. >vim
			execute '/' .. histget("search", -2)

<		Define an Ex command ":H {num}" that supports re-execution of
		the {num}th entry from the output of |:history|. >vim
			command -nargs=1 H execute histget("cmd", 0+<args>)
<

                Parameters: ~
                  • {history} (`string`)
                  • {index} (`integer|string?`)

                Return: ~
                  (`string`)

histnr({history})                                                     *histnr()*
		The result is the Number of the current entry in {history}.
		See |hist-names| for the possible values of {history}.
		If an error occurred, -1 is returned.

		Example: >vim
			let inp_index = histnr("expr")
<

                Parameters: ~
                  • {history} (`string`)

                Return: ~
                  (`integer`)

hlID({name})                                                            *hlID()*
		The result is a Number, which is the ID of the highlight group
		with name {name}.  When the highlight group doesn't exist,
		zero is returned.
		This can be used to retrieve information about the highlight
		group.  For example, to get the background color of the
		"Comment" group: >vim
			echo synIDattr(synIDtrans(hlID("Comment")), "bg")
<

                Parameters: ~
                  • {name} (`string`)

                Return: ~
                  (`integer`)

hlexists({name})                                                    *hlexists()*
		The result is a Number, which is TRUE if a highlight group
		called {name} exists.  This is when the group has been
		defined in some way.  Not necessarily when highlighting has
		been defined for it, it may also have been used for a syntax
		item.

                Parameters: ~
                  • {name} (`string`)

                Return: ~
                  (`0|1`)

hostname()                                                          *hostname()*
		The result is a String, which is the name of the machine on
		which Vim is currently running.  Machine names greater than
		256 characters long are truncated.

                Return: ~
                  (`string`)

iconv({string}, {from}, {to})                                          *iconv()*
		The result is a String, which is the text {string} converted
		from encoding {from} to encoding {to}.
		When the conversion completely fails an empty string is
		returned.  When some characters could not be converted they
		are replaced with "?".
		The encoding names are whatever the iconv() library function
		can accept, see ":!man 3 iconv".
		Note that Vim uses UTF-8 for all Unicode encodings, conversion
		from/to UCS-2 is automatically changed to use UTF-8.  You
		cannot use UCS-2 in a string anyway, because of the NUL bytes.

                Parameters: ~
                  • {string} (`string`)
                  • {from} (`string`)
                  • {to} (`string`)

                Return: ~
                  (`string`)

id({expr})