macrolists.hlp

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{smcl}
{* 09feb2004}{...}
{cmd:help macrolists}
{hline}

{title:Title}

{p2colset 5 24 26 2}{...}
{p2col :{hi:[P] macro lists} {hline 2}}Manipulation of lists{p_end}
{p2colreset}{...}


{title:Syntax}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{cmd:uniq}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{cmd:dups}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{cmd:sort}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{cmdab:retok:enize}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{cmd:clean}
{it:macname}


{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{it:macname}
{cmd:|}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{it:macname}
{cmd:&}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{it:macname}
{cmd:-}
{it:macname}


{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{it:macname}
{cmd:==}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{it:macname}
{cmd:===}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{it:macname}
{cmd:in}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{cmd:sizeof}
{it:macname}

{p 8 14 2}
{c -(}{cmdab:loc:al} | {cmdab:gl:obal}{c )-}
{it:macname}
{cmd::} {cmd:list}
{cmd:posof}
{cmd:"}{it:element}{cmd:"}
{cmd:in}
{it:macname}


{phang}
Note: Where {it:macname} appears, it is the name of macros and not their
contents that you are to type.  For example, you are to type

{pin2}
{cmd:local result : list list1 | list2}

{pmore}
and not

{pin2}
{cmd:local result : list "`list1'" | "`list2'"}

{pmore}
{it:macname}s that appear to the right of the colon are assumed to be the
names of local macros.  You may type {cmd:local(}{it:macname}{cmd:)} to
emphasize that fact.  Type {cmd:global(}{it:macname}{cmd:)} if you wish to
refer to a global macro.


{title:Description}

{pstd}
The extended macro function {cmd:list} manipulates lists.  See 
{helpb macro} for other extended macro functions.

{phang}
{cmd:uniq} {it:A} returns {it:A} with duplicate elements removed.  The
resulting list has the same ordering of its elements as {it:A}; duplicate
elements are removed from their rightmost position.
If {it:A}="{it:a b a c a}", {cmd:uniq} returns "{it:a b c}".

{phang}
{cmd:dups} {it:A} returns the duplicate elements of {it:A}.
If {it:A}="{it:a b a c a}", {cmd:dups} returns "{it:a a}".

{phang}
{cmd:sort} {it:A} returns {it:A} with its elements placed in alphabetical
(ascending ASCII) order.

{phang}
{cmd:retokenize} {it:A} returns {it:A} with single spaces between elements.
    Logically speaking, it makes no difference how many spaces a list has
    between elements, and thus {cmd:retokenize} leaves the list logically
    unchanged.

{phang}
{cmd:clean} {it:A} returns {it:A} retokenized and with each element adorned
    minimally.  An element is said to be unadorned if it is not enclosed in
    quotes (e.g., {it:a}).  Alternatively, an element may be adorned in simple
    or compound quotes (e.g., {cmd:"}{it:a}{cmd:"} or {cmd:`"}{it:a}{cmd:"'}).
    Logically speaking, it makes no difference how elements are adorned,
    assuming they are adorned adequately.  The list

{pin2}
{cmd:`"}{it:a}{cmd:"'} {cmd:`"}{it:b c}{cmd:"'} {cmd:`"}{it:b "c" d}{cmd:"'}

{pmore}
is equal to

{pin2}
{it:a} {cmd:"}{it:b c}{cmd:"} {cmd:`"}{it:b "c" d}{cmd:"'}

{pmore}
{cmd:clean}, in addition to performing the actions of {cmd:retokenize},
adorns each element minimally:  not at all if the element contains no
spaces or quotes, in simple quotes ({cmd:"} and {cmd:"}) if it contains spaces
but not quotes, and in compound quotes ({cmd:`"} and {cmd:"'}) otherwise.

{phang}
{it:A} {cmd:|} {it:B} returns the union of {it:A} and {it:B}, the result being
equal to {it:A} with elements of {it:B} not found in {it:A} added to the tail.
For instance, if {it:A}="{it:a b c}" and {it:B}="{it:b d e}", {it:A} {cmd:|}
{it:B} is "{it:a b c d e}".  If you instead want list concatenation, you
code,

{pin2}
{cmd:local} {it:newlist} {cmd:`"`}{it:A}{cmd:' `}{it:B}{cmd:'"'}

{pmore}
In the example above, this would return "{it:a b c b d e}".

{phang}
{it:A} {cmd:&} {it:B} returns the intersection of {it:A} and {it:B}.  If
{it:A}="{it:a b c d}" and {it:B}="{it:b c f g}", then {it:A} {cmd:&} {it:B} =
"{it:b c}".

{phang}
{it:A} {cmd:-} {it:B} returns a list containing elements of {it:A} with the
elements of {it:B} removed, with the resulting elements in the same order as
{it:A}.  For instance, if {it:A}="{it:a b c d}" and {it:B}="{it:b e}", the
result is "{it:a c d}".

{phang}
{it:A} {cmd:==} {it:B} returns 0 or 1; it returns 1 if {it:A} is equal to
{it:B}, if {it:A} has the same elements as {it:B} and in the same order.

{phang}
{it:A} {cmd:===} {it:B} returns 0 or 1; it returns 1 if {it:A} is equivalent
to {it:B}, if {it:A} has the same elements as {it:B} regardless of the order
in which the elements appear.

{phang}
{it:A} {cmd:in} {it:B} returns 0 or 1; it returns 1 if all elements of {it:A}
are found in {it:B}.  If {it:A} is empty, {cmd:in} returns 1.

{phang}
{cmd:sizeof} {it:A} returns the number of elements of {it:A}.
If {it:A}="{a b c}", {cmd:sizeof} {it:A} is 3.
(Note, {cmd:sizeof} returns the same result as the extended macro function
{help macro:word count}.)

{phang}
{cmd:posof} {cmd:"}{it:element}{cmd:"} {cmd:in} {it:A} returns the location of
{it:macname} in {it:A} or returns 0 if not found.  For instance, if {it:A}
contains "{it:a b c d}", then {cmd:posof "}{it:b}{cmd:" in} {it:A} returns 2.
({help macro:word # of} may be used to extract positional elements from lists,
as can {helpb tokenize} and {helpb gettoken}.)

{pmore}
Note that it is the element itself and not a macroname that you type as
the first argument.  In a program where macro {cmd:tofind} contained an element
to be found in list (macro) {cmd:variables}, you might code

{pin2}
{cmd:local i : list posof `"`tofind'"' in variables}

{pmore}
Note that {it:element} must be enclosed in quotes, which may be either simple
or compound.


{title:Remarks}

{pstd}
A {it:list} is a space-separated set of elements listed one after the other.
The individual elements may be enclosed in quotes and elements containing
spaces obviously must be enclosed in quotes.  The following are examples
of lists:

{pmore}
{cmd:this that what}

{pmore}
{cmd:"first element" second "third element" 4}

{pmore}
{cmd:this that what this that}

{pstd}
In addition, a list could be empty.

{pstd}
Do not confuse varlists with {it:lists}.  Varlists are a special notation,
such as "id m* pop*", which is a shorthand way of specifying a list of
variables; see {it:{help varlist}}.  Once expanded, however, a {it:varlist} is
a {it:list}.


{title:Treatment of adornment}

{pstd}
An element of a list is said to be adorned if it is enclosed in quotes.
Adornment, however, plays no role in the substantive interpretation
of lists.  The list

{pmore}
{it:a} {cmd:"}{it:b}{cmd:"} {it:c}

{pstd}
is identical to the list

{pmore}
{it:a b c}


{title:Treatment of duplicate elements in lists}

{pstd}
With the exception of {cmd:uniq} and {cmd:dups}, all list functions treat
duplicates as being distinct.  For instance, consider the list {it:A},

{pmore}
{it:a b c b}

{pstd}
Note that {it:b} appears twice in this list.
You want to think of the list as containing {it:a}, the first occurrence of
{it:b}, {it:c}, and the second occurrence of {it:b}:

{pmore}
{it:a b_1 c b_2}

{pstd}
Do the same thing with the duplicate elements of all lists, carry out the
operation on the now unique elements, and then erase the subscripts from
the result.

{pstd}
If you were to ask whether {it:B}="{it:b b}" is {cmd:in} {it:A}, the answer
would be yes, because {it:A} contains two occurrences of {it:b}.  If
{it:B} contained "{it:b b b}", however, the answer would be no because
{it:A} does not contain three occurrences of {it:b}.

{pstd}
Similarly, if {it:B}="{it:b b}", {it:A}{cmd:|}{it:B}="{it:a b c b}", but if
{it:B}="{it:b b b}", {it:A}{cmd:|}{it:B}="{it:a b c b b}".


{title:Also see}

{psee}
Manual:  {bf:[P] macro lists}

{psee}
Online:  {helpb macro}