Reverse words in a string: Difference between revisions

=={{header|Lambdatalk}}==

This answer illustrates how a missing primitive (line_split) can be added directly in the wiki page.

<lang scheme>

1) We write a function

{def line_reverse

{def line_reverse.r

{lambda {:i :txt :length}

{if {> :i :length}

then

else {br}{A2S {A.reverse! {A.get :i :txt}}}

{line_reverse.r {+ :i 1} :txt :length}}}}

{lambda {:txt}

{let { {:a {line_split {:txt}}} }

{line_reverse.r 0 :a {- {A.length :a} 1}}}} }

-> line_reverse

where A2S translates an array into a sentence

{def A2S

{lambda {:a}

{if {A.empty? :a}

then

else {A.first :a} {A2S {A.rest :a}}}}}

-> A2S

and line_split is a javascript primitive directly written in the wiki page,

added to the dictionary and returning an array of lines

LAMBDATALK.DICT['line_split'] = function () {

var args = arguments[0].split("\n");

var str = "{A.new ";

for (var i=0; i< args.length; i++)

str += "{A.new " + args[i] + "} ";

str += "}";

return LAMBDATALK.eval_forms( str )

};

2) input (from a simple text source without any presetting)

{def rosetta

---------- Ice and Fire ------------

fire, in end will world the say Some

ice. in say Some

desire of tasted I''ve what From

fire. favor who those with hold I

... elided paragraph last ...

Frost Robert -----------------------

}

-> rosetta

3) calling the function:

{line_reverse rosetta}

->

3) output

------------ Fire and Ice ----------

Some say the world will end in fire,

Some say in ice.

From what I''ve tasted of desire

I hold with those who favor fire.

... last paragraph elided ...

----------------------- Robert Frost

</lang>