HP 3000 Manuals HP 3000 Manuals
PATTERN MATCH
Used to test a field value against a pattern of characters.
Syntax
MATCH pattern ["message"]
Parameters
pattern A pattern of characters which indicate which type of
character in which position is acceptable input for this
field.
message Specifies a custom error message.
Discussion
The pattern match allows you to check field values against a general
pattern. It can be used to check the actual value, but actual values are
more easily checked in the Single Value, Table, or Range tests. This
test is generally used to test the type of character entered in a
particular position. Before data is checked against a pattern, any
leading and trailing blanks are stripped.
NOTE Native Language Support does not support pattern matching with
native language characters. MATCH uses USASCII (NATIVE-3000)
rules. For more information on Native Language Support, see
Section 8.
Special Pattern Characters
The pattern consists of a series of special characters that indicate the
type of USASCII data that can be entered in that position. These
characters are:
a upper or lowercase alphabetic character (A-Z, a-z)
u uppercase alphabetic character (A-Z)
l lowercase alphabetic character (a-z)
b blank
d digit (0-9)
? any character
The beginning of the pattern is defined by the first nonblank character
after MATCH and, in the simplest case, is terminated by the first blank
encountered. A pattern beginning or ending with the special character b
will interpret the b as the alphabetic character and not the special
character indicating a blank. Leading and trailing blanks should be
indicated as spaces within a grouping as described on the next page.
A pattern may contain embedded blanks only if it is enclosed within
braces {}. Also, a pattern can span more than one line if it is enclosed
within braces {}. If a pattern is within braces, it is terminated by the
first blank outside the braces.
The match pattern can include specific characters in addition to the
types listed above. To illustrate:
MATCH Aaa-ddd
This pattern means that the value must start with the letter A, be
followed by any two upper or lowercase letters of the alphabet, followed
by a hyphen and then three digits. For example, the value Acs-123 or
AAA-999 are acceptable, but the values Bcs-999 or A12-345 are not.
Transparency
A special operator can be used to indicate that a pattern character is to
be used as an actual value. For example, suppose you want the lowercase
letter a to be an exact value in the pattern. You can do this by
preceding it, or any of the other special pattern characters, with an
exclamation point (!). For example:
MATCH !addd \Value must start with the letter "a"
\followed by any three digits.
The exclamation point (called the transparency user) is also used to
allow inclusion of any of the pattern operators listed below, and
described in Table 4-3.
! (tranparency)
, (choice)
: (range)
{} (grouping)
[] (optional)
+ (repetition--1 or more)
* (repetition--O or more)
Choice
You can indicate a selection of acceptable patterns as part of the MATCH
pattern. Each possible choice is separated by a comma (,). For example:
MATCH A,AB,BCD,ddd \The characters "A", "AB", "BCD",
\or any three digits are acceptable.
Range
A range of acceptable characters for a single character position can be
indicated with the colon (:). All characters within the range are
acceptable. This acts as a shorthand for listing a series of single
characters in USASCII sequence. For example:
MATCH C:J This is equivalent to the pattern specified by MATCH
C,D,E,F,G,H,I,J.
MATCH 1:7 Any of the digits 1,2,3,4,5,6, or 7 is accepted by this
pattern.
MATCH !a:f Since the letter a is a pattern character, it is
preceded by an exclamation point. Other such characters
within the range are implicitly preceded by this
operator. Thus, the range is equivalent to specifying
MATCH !a,!b,c,!d,e,f.
It is important to differentiate between a pattern range which is a range
of single characters, and the range check described earlier. In a
pattern check, MATCH 10:90 means the value must be a 1 followed by a
digit between 0 and 9, followed a 0. In a range check, IN 10:90 means
the value must be in the range 10 through 90.
Grouping and Optional
You can group pattern specifications by enclosing the pattern in braces
{}. Brackets [] make the enclosed pattern optional. Braces indicate
data must correspond to at least one item in the group; brackets indicate
any item in the group is optional. For example:
MATCH One of the choices within braces must be matched. For
{A,AB,BCD}) ddd example: A123 or AB999 or BCD562, among others, are
acceptable matches for this pattern.
MATCH All choices within brackets can be omitted, or one may
[A,AB,BCD] ddd be matched. For example: AB345, BCD567, A441, or 123
are all acceptable matches.
MATCH [u,d]!+ Some acceptable values are A+ or 5+3 or +5 or simply +.
[1:5]
MATCH Accepts such values as B12 or 12345 or 50% or 10, among
[B,dd]dd[%,d] others.
Since blanks may be included within braces, you can put blanks in a
pattern to enhance its clarity by enclosing the entire pattern within
braces. For example:
MATCH {[B,dd] Identical to preceding pattern except that it is
dd [%,d]} enclosed within braces so that blanks can be included.
Enclosing a pattern within braces also allows the pattern to span lines.
For example:
MATCH {[B,dd] Identical to the example above, except that each pattern
dd [%,d]} component is listed on a separate line.
Repetition
Repetition of any character or sets of characters can be indicated by an
asterisk (*) or by a plus sign (+) following any pattern character or
pattern group within braces. Plus (+) means that at least one occurrence
of the pattern is required for the match; the asterisk (*) means that
zero or more occurrences can be matched. These repetition indicators
cannot follow items enclosed within brackets. Some examples:
MATCH d+ The plus sign indicates repetition of the digit, with at
least one occurrence required for the match. Leaving
the field blank is not acceptable unless the field type
is 0 for optional, in which case a blank is accepted
because processing specifications are ignored.
For example, 2 or 7654321 or 55 are acceptable.
MATCH Xd+ This pattern accepts the letter X followed by one or
more digits.
For example, X1 or X2345, and so forth are acceptable,
but not X.
MATCH M{A,C,d}+ A plus sign after a pair of braces indicates repetition
of any item within the braces, in any order.
Some acceptable values are MA, MCCC, or M12333CAA9.
MATCH d* The asterisk indicates optional repetition that allows
zero or more occurrences of the pattern. Thus, the
digit can be omitted, or repeated any number of times.
For example, nothing, or 3, or 123456, and so forth are
acceptable matches.
MATCH [d+] This pattern is another way of expressing the pattern
shown above as d*.
MATCH a* Accepts any alphabetic or empty string.
MATCH Xu* This pattern accepts X alone, or followed by any number
of uppercase letters.
For example, XABC or XX or X are all acceptable.
MATCH M{A,C,d}* Any of the enclosed characters can be repeated in any
order, or can be omitted.
Thus, M is acceptable, as are MAA, MCCAC12, MA63CCA5,
and so forth.
Operator Hierarchy
Table 4-6 summarizes the operators allowed in a MATCH pattern. The
pattern operators are evaluated in the following order, where x and y are
any patterns:
Highest !x Transparency
| x:y Range
| x+ or x* Repetition
v xy Concatenation
Lowest x,y Choice
Table 4-6. Pattern Match Operators
-----------------------------------------------------------------------------------------------
| | | |
| Operator | Function | Example |
| | | |
-----------------------------------------------------------------------------------------------
| | | |
| ! | Transparency operator that allows | MATCH !u,!d,!,,!! accepts any of |
| Exclamation | use of any special MATCH | the values u, d,,, or !. |
| point | characters as an element in the | |
| | pattern. | |
| | | |
-----------------------------------------------------------------------------------------------
| | | |
| , | Choice of subpatterns, any one of | MATCH A,B, dd accepts values such |
| Comma | which satisfies the match. | as A,B, and 22. |
| | | |
-----------------------------------------------------------------------------------------------
| | | |
| : | Range of single characters in | MATCH 2:6 accepts only the values |
| Colon | ascending collating order, any one | 2,3,4,5, or 6. |
| | of which satisfies the match. | |
| | | |
-----------------------------------------------------------------------------------------------
| | | |
| { } | Required grouping that specifies | MATCH {A,B}dd{%,d} accepts A223, |
| Braces | at least one occurrence of any | B34%,A795, and so forth. |
| | pattern within braces. | |
| | | |
-----------------------------------------------------------------------------------------------
| | | |
| [ ] | Optional grouping that allows zero | MATCH [A,B]dd[%,d] accepts 24,A99, |
| Brackets | or one occurrence of any item in | 10%,123, and so forth. |
| | pattern within brackets. | |
| | | |
-----------------------------------------------------------------------------------------------
| | | |
| + | Required repetition that specifies | MATCH Xd+ accepts values such as |
| Plus | at least one or more occurrences | X1,X22, X3334789, and so forth, |
| | of a preceding item, or a pattern | but not X. MATCH {d,a} + accepts |
| | within braces. | values such as 11,A23,acb, or |
| | | 33ABC9. |
| | | |
-----------------------------------------------------------------------------------------------
| | | |
| * | Optional repetition that allows | MATCH Xd* accepts values such as |
| Asterisk | zero or more occurrences of a | X,X1, X22, and X3334789. MATCH |
| | preceding item or a pattern within | {d,a}* accepts a null value, or |
| | braces. | such values as 11,A23,acb, or |
| | | 33ABC9. |
| | | |
-----------------------------------------------------------------------------------------------
Example
Some further examples of the MATCH statement are:
MATCH 1dddd Accepts an integer between 10000 and
19999. Could also be expressed as: IN
10000:19999.
MATCH [d]d!:dd [AM,PM] Accepts a time such as 3:00 PM or 12:00.
MATCH {1:9,1(0:2}}!: Accepts 12-hour clock time, such as 12:15
{0:5}db*[{A,P} [M]] PM or 01:30 AM.
MATCH {1:7}{0:7} * Accepts an octal number greater than zero
with at least one digit and no leading
zeros, such as 2047, or 1 or 24.
MATCH ddd-dd-dddd Accepts any United States Social Security
number, such as 044-24-0474.
MATCH [(ddd)]b*ddd- dddd Accepts a United States phone number with
an optional area code.