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Great article by Jim Martin on %replace
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The %replace BIF has been with RPG IV since V4R2,
but my guess is that not many programmers routinely use it.
It's a highly loaded BIF, meaning that it can perform many different
functions. It has four parameters and the following general format:
%replace(from-string:to-string{:starting-position{:length}})
This BIF returns a character string.
The first function, and most obvious based on its name, is a
character replacement in a character-string variable. This BIF
is different from the %subst BIF in that neither the from-string
nor the to-string parameters are modified as a result of using
the %replace BIF. Let's compare %replace and %subst with an
Let's assume we want to put four characters from Field2, starting
at position 3, into Field1, starting at position 3. The answer needs
to go in field Answer, without modifying either Field1 or Field2.
The example above shows a simple one-to-one replacement,
all done in one instruction.
Another useful application of %replace is to emulate the
fixed-format Movel operation. The Eval operation can emulate
Movel with blank padding, but it doesn't do so well without
padding. The %replace BIF can emulate Movel without padding.
This will be helpful if you have decided to convert to
free-format RPG IV, where Movel is not available.
Let's assume we want to replace the first two characters of
Field1 with 'XY', coming from the field TwoChar:
The next function to be illustrated is character-string insertion.
To clarify, think of how you insert text into a word document
using a PC document editor. The editor inserts text at the desired
point as you type.
The 0 for length sets the function to insert text. The field
Answer now contains 'She sells sea shells'. Notice that Text1
is too small to contain the result, but Answer is large enough.
If by chance Answer is too small to contain the complete new
string, trailing characters are truncated without a program
exception.
Using the %replace BIF eliminates the need for complex
sub-stringing and concatenation expressions.
The last function to be explained is the string-deletion function.
Again, think of how you delete characters in a string when
using a PC document editor. The editor removes a character at
the desired point as you strike the Delete key.
The two consecutive apostrophes in the first parameter tell
the BIF to delete. Field Answer now contains 'She sells shells'.
Text1 is not modified.
The %replace BIF has no counterpart in CL or original fixed-format
RPG operation codes. These marvelous character-string functions can
make your data manipulation programming easier to code and maintain.
Try it!
for more articles by Jim
The %replace BIF has been with RPG IV since V4R2,
but my guess is that not many programmers routinely use it.
It's a highly loaded BIF, meaning that it can perform many different
functions. It has four parameters and the following general format:
%replace(from-string:to-string{:starting-position{:length}})
This BIF returns a character string.
The first function, and most obvious based on its name, is a
character replacement in a character-string variable. This BIF
is different from the %subst BIF in that neither the from-string
nor the to-string parameters are modified as a result of using
the %replace BIF. Let's compare %replace and %subst with an
Code:
example:
D Field1 S 9 Inz('abcdefghi')
D Field2 S 9 Inz('ZYXWVUTSR')
D Answer S 14
at position 3, into Field1, starting at position 3. The answer needs
to go in field Answer, without modifying either Field1 or Field2.
Code:
Using %subst: /free Answer = Field1; %subst(Answer:3:4) = %subst(Field2:3:4); // Answer= 'abXWVUghi'
Code:
Using %replace: /free Answer = %replace(Field2:Field1:3:4); // Answer= 'abXWVUghi'
The example above shows a simple one-to-one replacement,
all done in one instruction.
Another useful application of %replace is to emulate the
fixed-format Movel operation. The Eval operation can emulate
Movel with blank padding, but it doesn't do so well without
padding. The %replace BIF can emulate Movel without padding.
This will be helpful if you have decided to convert to
free-format RPG IV, where Movel is not available.
Code:
Here's an example:
D Field1 S 6 Inz('ABCDEF')
D TwoChar S 2 Inz('XY')
Field1 with 'XY', coming from the field TwoChar:
Code:
/free Field1 = %replace(TwoChar:Field1); // Field1 is now 'XYCDEF'
To clarify, think of how you insert text into a word document
using a PC document editor. The editor inserts text at the desired
point as you type.
Code:
Consider the following example:
D Text1 S 16 Inz('She sells shells')
D NewChar S 4 Inz('sea')
D Answer S 30
/free
Answer = %replace(NewChar:Text1:11:0);
The 0 for length sets the function to insert text. The field
Answer now contains 'She sells sea shells'. Notice that Text1
is too small to contain the result, but Answer is large enough.
If by chance Answer is too small to contain the complete new
string, trailing characters are truncated without a program
exception.
Using the %replace BIF eliminates the need for complex
sub-stringing and concatenation expressions.
The last function to be explained is the string-deletion function.
Again, think of how you delete characters in a string when
using a PC document editor. The editor removes a character at
the desired point as you strike the Delete key.
PHP Code:
Consider the following example:
D Text1 S 23 Inz('She really sells shells')
D Answer S 30
/free
Answer = %replace('':Text1:5:7);
The two consecutive apostrophes in the first parameter tell
the BIF to delete. Field Answer now contains 'She sells shells'.
Text1 is not modified.
The %replace BIF has no counterpart in CL or original fixed-format
RPG operation codes. These marvelous character-string functions can
make your data manipulation programming easier to code and maintain.
Try it!
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