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diff --git a/doc/mapeach.n b/doc/mapeach.n deleted file mode 100644 index c89f7d9..0000000 --- a/doc/mapeach.n +++ /dev/null @@ -1,91 +0,0 @@ -'\" -'\" Copyright (c) 2012 Trevor Davel -'\" -'\" See the file "license.terms" for information on usage and redistribution -'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. -'\" -.so man.macros -.TH mapeach n "" Tcl "Tcl Built-In Commands" -.BS -'\" Note: do not modify the .SH NAME line immediately below! -.SH NAME -mapeach \- Iterate over all elements in one or more lists and collect results -.SH SYNOPSIS -\fBmapeach \fIvarname list body\fR -.br -\fBmapeach \fIvarlist1 list1\fR ?\fIvarlist2 list2 ...\fR? \fIbody\fR -.BE - -.SH DESCRIPTION -.PP -The \fBmapeach\fR command implements a loop where the loop -variable(s) take on values from one or more lists, and the loop returns a list -of results collected from each iteration. -.PP -In the simplest case there is one loop variable, \fIvarname\fR, -and one list, \fIlist\fR, that is a list of values to assign to \fIvarname\fR. -The \fIbody\fR argument is a Tcl script. -For each element of \fIlist\fR (in order -from first to last), \fBmapeach\fR assigns the contents of the -element to \fIvarname\fR as if the \fBlindex\fR command had been used -to extract the element, then calls the Tcl interpreter to execute -\fIbody\fR. If execution of the body completes normally then the result of the -body is appended to an accumulator list. \fBmapeach\fR returns the accumulator -list. - -.PP -In the general case there can be more than one value list -(e.g., \fIlist1\fR and \fIlist2\fR), -and each value list can be associated with a list of loop variables -(e.g., \fIvarlist1\fR and \fIvarlist2\fR). -During each iteration of the loop -the variables of each \fIvarlist\fR are assigned -consecutive values from the corresponding \fIlist\fR. -Values in each \fIlist\fR are used in order from first to last, -and each value is used exactly once. -The total number of loop iterations is large enough to use -up all the values from all the value lists. -If a value list does not contain enough -elements for each of its loop variables in each iteration, -empty values are used for the missing elements. -.PP -The \fBbreak\fR and \fBcontinue\fR statements may be -invoked inside \fIbody\fR, with the same effect as in the \fBfor\fR -and \fBforeach\fR commands. In these cases the body does not complete normally -and the result is not appended to the accumulator list. -.SH EXAMPLES -.PP -Zip lists together: -.PP -.CS -'\" Maintainers: notice the tab hacking below! -.ta 3i -set list1 {a b c d} -set list2 {1 2 3 4} -set zipped [\fBmapeach\fR a $list1 b $list2 {list $a $b}] -# The value of zipped is "{a 1} {b 2} {c 3} {d 4}" -.CE -.PP -Filter a list: -.PP -.CS -set values {1 2 3 4 5 6 7 8} -proc isGood {n} { expr { ($n % 2) == 0 } } -set goodOnes [\fBmapeach\fR x $values {expr {[isGood $x] ? $x : [continue]}}] -# The value of goodOnes is "2 4 6 8" -.CE -.PP -Take a prefix from a list: -.PP -.CS -set values {8 7 6 5 4 3 2 1} -proc isGood {n} { expr { $n > 3 } } -set prefix [\fBmapeach\fR x $values {expr {[isGood $x] ? $x : [break]}}] -# The value of prefix is "8 7 6 5 4" -.CE - -.SH "SEE ALSO" -for(n), while(n), break(n), continue(n), foreach(n) - -.SH KEYWORDS -foreach, iteration, list, loop, map |