.TH edlin_expand 3erl "stdlib 5.2.2" "Ericsson AB" "Erlang Module Definition"
.SH NAME
edlin_expand \- Shell expansion and formatting of expansion suggestions.
.SH DESCRIPTION
.LP
This module provides an expand_fun for the erlang shell \fIexpand/1,2\fR\&\&. It is possible to override this expand_fun \fIio:setopts/1,2\fR\&\&.
.SH EXPORTS
.LP
.nf

.B
expand(Bef0) -> {Res, Completion, Matches}
.br
.fi
.br
.nf

.B
expand(Bef0, Opts) -> {Res, Completion, Matches}
.br
.fi
.br
.RS
.LP
Types:

.RS 3
Bef0 = string()
.br
Opts = [Option]
.br
Option = {legacy_output, boolean()}
.br
Res = yes | no
.br
Completion = string()
.br
Matches = [Element] | [Section]
.br
Element = {string(), [ElementOption]}
.br
ElementOption = {ending, string()}
.br
Section = 
.br
    #{title := string(),
.br
      elems := Matches,
.br
      options := SectionOption}
.br
SectionOption = 
.br
    {highlight_all} |
.br
    {highlight, string()} |
.br
    {highlight_param, integer()} |
.br
    {hide, title} |
.br
    {hide, result} |
.br
    {separator, string()}
.br
.RE
.RE
.RS
.LP
The standard expansion function is able to expand strings to valid erlang terms\&. This includes module names:
.LP
.nf

1> erla
modules
erlang:
        
.fi
.LP
function names:
.LP
.nf

1> is_ato
functions
is_atom(
2> erlang:is_ato
functions
is_atom(
    
.fi
.LP
function types:
.LP
.nf

1> erlang:is_atom(
typespecs
erlang:is_atom(Term)
any()

.fi
.LP
and automatically add , or closing parenthesis when no other valid expansion is possible\&. The expand function also completes: shell bindings, record names, record fields and map keys\&.
.LP
As seen below, function headers are grouped together if they\&'ve got the same expansion suggestion, in this case all had the same suggestions, that is \&'}\&'\&. There is also limited support for filtering out function typespecs that that does not match the types on the terms on the prompt\&. Only 4 suggestions are shown below but there exists plenty more typespecs for \fIerlang:system_info\fR\&\&.
.LP
.nf

1> erlang:system_info({allocator, my_allocator
typespecs
erlang:system_info(wordsize | {wordsize, ...} | {wordsize, ...})
erlang:system_info({allocator, ...})
erlang:system_info({allocator_sizes, ...})
erlang:system_info({cpu_topology, ...})
}

.fi
.LP
The return type of \fIexpand\fR\& function specifies either a list of \fIElement\fR\& tuples or a list of \fISection\fR\& maps\&. The section concept was introduced to enable more formatting options for the expansion results\&. For example, the shell expansion has support to highlight text and hide suggestions\&. There are also a \fI{highlight, Text}\fR\& that highlights all occurances of \fIText\fR\& in the title, and a \fIhighlight_all\fR\& for simplicity which highlights the whole title, as can be seen above for \fIfunctions\fR\& and \fItypespecs\fR\&\&.
.LP
By setting the \fI{hide, result}\fR\& or \fI{hide, title}\fR\& options you may hide suggestions\&. Sometimes the title isn\&'t useful and just produces text noise, in the example above the \fIany()\fR\& result is part of a section with title \fITypes\fR\&\&. Hiding results is currently not in use, but the idea is that a section can be selected in the expand area and all the other section entries should be collapsed\&.
.LP
Its possible to set a custom separator between the title and the results\&. This can be done with \fI{separator, Separator}\fR\&\&. By default its set to be \fI\\n\fR\&, some results display a \fItype_name() :: \fR\& followed by all types that define \fItype_name()\fR\&\&.
.LP
The \fI{ending, Text}\fR\& ElementOption just appends Text to the \fIElement\fR\&\&.
.RE