SORT-MERGE/XL General User's Guide (32650-90883)

ManualsBrandsHP ManualsSoftwareMPE/iX 6.0 Operating System

68 Chapter6

SORT-MERGE/XL Commands

ALTSEQ

DISCUSSION

Each modiﬁcation of the collating sequence changes the ordinal values in the translation

table assigned to the characters speciﬁed by

leftspec

. Refer to the >SHOW command for a

discussion of the translation table. If

rightspec

is longer than

leftspec

, the extra

characters are ignored. If

leftspec

is longer than

rightspec

and neither EACH nor MERGE

has been speciﬁed,

rightspec

is padded with blanks to make it equal in length to

leftspec

. For example, the command, >ALTSEQ "SAW"="TG" gives S, A, and W the ordinal

values T, G, and space. (See the discussion below for explanations of

modspec

with EACH

and MERGE.) These assignments of new ordinal values are only for collating purposes. That

is, the identity of the character is not lost; data is unchanged and appears in its original

form in the output.

You must issue a >DATA command, specifying data type and a collating sequence type

before you can use the >ALTSEQ command in any SORT/XL or MERGE/XL operation. The

system displays the error message THE DATA COMMAND MUST BE ISSUED BEFORE THE

ALTSEQ COMMAND CAN BE ISSUED, if the >ALTSEQ command is not preceded by a >DATA

command.

NOTE

The operation of SORT/XL (or MERGE/XL) is slower when you deﬁne a

collating sequence with the >ALTSEQ command than when a standard ASCII

or EBCDIC collating sequence is used.

Using modspec With EACH

If EACH is speciﬁed, the modiﬁcations of the collating sequence are the same as explained

above, except if

leftspec

is longer than

rightspec

is concatenated to itself a

sufﬁcient number of times to make it equal in length to

leftspec

. For example, the

command, >ALTSEQ EACH "ADW"="FG", give A, D, and W the ordinal values obtained by

taking the ASCII code decimal values of F, G, and F. Assuming the basic collating sequence

has been speciﬁed as ASCII, this means A=70 appears in the sixth row, ﬁfth column of the

translation table, D=71 in the sixth row, eighth column, and W=70 in the eighth row,

seventh column. Note that 70 and 71 are the ASCII code decimal values of the characters F

and G, respectively. For additional information refer to the "EXAMPLES" section below.

Using modspec With MERGE

When MERGE is speciﬁed in the

modspec

parameter, the values in the translation table

assigned to the characters speciﬁed by

leftspec

and

rightspec

, and the characters in

between are modiﬁed. Characters are selected alternatively from

leftspec

and

rightspec

and the translation table is modiﬁed so the characters collate in this order. The

ﬁrst character is always selected from

leftspec

. If

leftspec

precedes

rightspec

in the

collating sequence, the sequence is modiﬁed so the characters between the two ranges

collate after the merger of the ranges. If

rightspec

precedes

leftspec

, the characters

between the two ranges collate before the ﬁrst character of the ﬁrst range. When either

range is exhausted, the characters from the other range are simply appended until that

range is also exhausted. Note that the strings speciﬁed by

leftspec

and

rightspec

must

be strictly increasing and contiguous whenever MERGE is speciﬁed.