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Diffstat (limited to 'doc/lseq.n')
| -rw-r--r-- | doc/lseq.n | 130 |
1 files changed, 77 insertions, 53 deletions
@@ -11,85 +11,109 @@ .SH NAME lseq \- Build a numeric sequence returned as a list .SH SYNOPSIS -\fBlseq \fIStart \fR?(\fB..\fR|\fBto\fR)? \fIEnd\fR ??\fBby\fR? \fIStep\fR? +\fBlseq \fIstart \fR?(\fB..\fR|\fBto\fR)? \fIend\fR ??\fBby\fR? \fIstep\fR? -\fBlseq \fIStart \fBcount\fR \fICount\fR ??\fBby\fR? \fIStep\fR? +\fBlseq \fIstart \fBcount\fR \fIcount\fR ??\fBby\fR? \fIstep\fR? -\fBlseq \fICount\fR ?\fBby \fIStep\fR? +\fBlseq \fIcount\fR ?\fBby \fIstep\fR? .BE .SH DESCRIPTION .PP The \fBlseq\fR command creates a sequence of numeric values using the given -parameters \fIStart\fR, \fIEnd\fR, and \fIStep\fR. The \fIoperation\fR -argument ".." or "to" defines the range. The "count" option is used -to define a count of the number of elements in the list. A short form use of -the command, with a -single count value, will create a range from 0 to count-1. - -The \fBlseq\fR command can produce both increasing and decreasing sequences. When -both Start and End are provided without a Step value, then if Start <= End, -the sequence will be increasing and if Start > End it will be decreasing. If a -Step vale is included, it's sign should agree with the direction of the +parameters \fIstart\fR, \fIend\fR, and \fIstep\fR. The \fIoperation\fR +argument "\fB..\fR" or "\fBto\fR" defines the range. The "\fBcount\fR" option +is used to define a count of the number of elements in the list. A short form +use of the command, with a single count value, will create a range from 0 to +count-1. + +The \fBlseq\fR command can produce both increasing and decreasing +sequences. When both \fIstart\fR and \fIend\fR are provided without a +\fIstep\fR value, then if \fIstart\fR <= \fIend\fR, the sequence will be +increasing and if \fIstart\fR > \fIend\fR it will be decreasing. If a +\fIstep\fR vale is included, it's sign should agree with the direction of the sequence (descending -> negative and ascending -> positive), otherwise an empty list is returned. For example: .CS \" - % lseq 1 to 5 ;# increasing - 1 2 3 4 5 +% \fBlseq\fR 1 to 5 ;# increasing +\fI\(-> 1 2 3 4 5 - % lseq 5 to 1 ;# decreasing - 5 4 3 2 1 +% \fBlseq\fR 5 to 1 ;# decreasing +\fI\(-> 5 4 3 2 1 - % lseq 6 to 1 by 2 ;# decreasing, step wrong sign, empty list +% \fBlseq\fR 6 to 1 by 2 ;# decreasing, step wrong sign, empty list - % lseq 1 to 5 by 0 ;# all step sizes of 0 produce an empty list +% \fBlseq\fR 1 to 5 by 0 ;# all step sizes of 0 produce an empty list +.\" +.CE +The numeric arguments, \fIstart\fR, \fIend\fR, \fIstep\fR, and \fIcount\fR, +may also be a valid expression. The expression will be evaluated and the +numeric result will be used. An expression that does not evaluate to a number +will produce an invalid argument error. +.PP +\fIStart\fR defines the initial value and \fIend\fR defines the limit, not +necessarily the last value. \fBlseq\fR produces a list with \fIcount\fR +elements, and if \fIcount\fR is not supplied, it is computed as + +.CS \" + \fIcount\fR = int( (\fIend\fR - \fIstart\fR + \fIstep\fR) / \fIstep\fR ) .\" .CE -The numeric arguments, \fIStart\fR, \fIEnd\fR, \fIStep\fR, and \fICount\fR, -may also be a valid expression. The expression will be evaluate and the -numeric result be used. An expression that does not evaluate to a number will -produce an invalid argument error. +.PP +The numeric arguments, \fIstart\fR, \fIend\fR, \fIstep\fR, and \fIcount\fR, +can also be a valid expression. the \fBlseq\fR command will evaluate the +expression (as if with \fBexpr\fR) +and use the numeric result, or return an error as with any invalid argument +value; a non-numeric expression result will result in an error. .SH EXAMPLES .CS .\" +\fBlseq\fR 3 +\fI\(-> 0 1 2\fR - lseq 3 - \(-> 0 1 2 - - lseq 3 0 - \(-> 3 2 1 0 +\fBlseq\fR 3 0 +\fI\(-> 3 2 1 0\fR - lseq 10 .. 1 by -2 - \(-> 10 8 6 4 2 +\fBlseq\fR 10 .. 1 by -2 +\fI\(-> 10 8 6 4 2\fR - set l [lseq 0 -5] - \(-> 0 -1 -2 -3 -4 -5 +set l [\fBlseq\fR 0 -5] +\fI\(-> 0 -1 -2 -3 -4 -5\fR - foreach i [lseq [llength $l]] { - puts l($i)=[lindex $l $i] - } - \(-> l(0)=0 - l(1)=-1 - l(2)=-2 - l(3)=-3 - l(4)=-4 - l(5)=-5 - - foreach i [lseq [llength $l]-1 0] { +foreach i [\fBlseq\fR [llength $l]] { + puts l($i)=[lindex $l $i] +} +\fI\(-> l(0)=0\fR +\fI\(-> l(1)=-1\fR +\fI\(-> l(2)=-2\fR +\fI\(-> l(3)=-3\fR +\fI\(-> l(4)=-4\fR +\fI\(-> l(5)=-5\fR + +foreach i [\fBlseq\fR {[llength $l]-1} 0] { puts l($i)=[lindex $l $i] - } - \(-> l(5)=-5 - l(4)=-4 - l(3)=-3 - l(2)=-2 - l(1)=-1 - l(0)=0 - - set sqrs [lmap i [lseq 1 10] {expr $i*$i}] - \(-> 1 4 9 16 25 36 49 64 81 100 +} +\fI\(-> l(5)=-5\fR +\fI\(-> l(4)=-4\fR +\fI\(-> l(3)=-3\fR +\fI\(-> l(2)=-2\fR +\fI\(-> l(1)=-1\fR +\fI\(-> l(0)=0\fR + +set i 17 + \fI\(-> 17\fR +if {$i in [\fBlseq\fR 0 50]} { # equivalent to: (0 <= $i && $i <= 50) + puts "Ok" +} else { + puts "outside :(" +} +\fI\(-> Ok\fR + +set sqrs [lmap i [\fBlseq\fR 1 10] { expr {$i*$i} }] +\fI\(-> 1 4 9 16 25 36 49 64 81 100\fR .\" .CE .SH "SEE ALSO" |