Simple Text Patterns and Regular Expressions

Simple Text Patterns

A simple text pattern is a combination of characters that can be supplemented by an asterisk '*' as a placeholder for any number of any type of character.

You can use simple text patterns when searching for names.

Examples of simple patterns:

• Anna returns Anna
• An* returns Anna and Anthony
• *nn* returns Anna and Hannah

Using Regular Expressions

You can use text patterns or regular expressions in various Innovator components to specify not just a single string but a set of strings that all match the text pattern or the regular expression.

Regular expressions are used in Innovator in the following places:

• In the Innovator model editor when searching for contained text in specification texts or annotations

• In the configuration editor to describe a name constraint

  Here, an entered name is checked for validity against this pattern and then approved or rejected.

The regular expressions in Innovator use a subset of the options for forming text patterns described, for example, in Wikipedia (http://en.wikipedia.org/wiki/Regular_expression).

Forming Regular Expressions

This section explains how to form regular expressions.

• In Innovator, regular expressions are always evaluated within a paragraph.

  Example:

  Searching for class.*multiple returns the following text.

  Searching for class.*attributes does not return this text.

  The class has multiple

  - attributes

  -methods

• Each character is represented by itself apart from the special meta character:

  [ ] ( ) { } | ? + - . * ^ $ \

• If you want to search for special meta characters themselves, they must be masked with a backslash '\'.

  Examples:

  surname\\first name returns surname\first name

  \[a\] returns [a]

  \^hat returns ^hat

  dollar\$ returns dollar$

• The minus sign '-' only has a special meaning if it is in square brackets.

• A set of characters is defined between square brackets []. The expression then stands for a character from this set.

  The set can be defined by enumeration of its elements and/or specifying an area in the ASCII table. Such ranges are specified by their first and last characters, separated by a minus sign '-'.

  Within these square brackets, special characters have no meaning, i.e. '\', '$', '^', and '.' represent themselves. This means that the beginning of a line cannot be defined as an element of a set, for example. However, the hat '^' has another special meaning in a certain position within square brackets. If a hat '^' immediately follows an opening square bracket '[', the complement of the specified set is searched for.

  Examples:

  m[aiu]ster returns master, mister or muster

  test[1-4] returns test1, test2, test3 or test4

  [^A-Za-z] returns all characters apart from letters

• A period '.' represents any character.

  Example:

  function(.) returns function(a), function(3) ...

• Any multiplicities of the preceding expression are shown in curly brackets {}.

  Examples:

  {n} indicates that the expression must exist precisely n times

  {n,} indicates that the expression must exist n times

  {n,m} indicates that the expression must exist at least n times and no higher than m times

  {0,m} indicates that the expression must no exist more than m times

• A question mark '?' indicates that the preceding expression may optionally exist and corresponds to {0,1}.

  Example:

  D[- ]?[0-9]{5} finds German zip code with the country code 'D', 'D ' or 'D-'.

• An asterisk '*' indicates the number of repetitions of the preceding expression (also none) and corresponds to {0,}.

  Examples:

  off[a-z]* returns off, offline, office ...

  [1-9][0-9]* returns all natural numbers

• A plus '+' indicates that the preceding expression exists at least once and corresponds to {1,}.

  Example:

  [ab]+ finds a, b, aa, bbaab etc.

• A hat '^' represents the beginning of a line.

  Example:

  ^variable returns variables at the beginning of a line

• The dollar sign '$' represents the end of a line.

  Example:

  term;$ returns term; at the end of a line

• The vertical line '|' means 'or'. Here, the alternatives are separated from the remaining text using parentheses.

  Example:

  (in|out)put returns input and output

  A more complex example for a date (does not check for the number of days in a given month!):

  ^(0[1-9]|[12][0-9]|3[0-1])\.(0[1-9]|1[0-2])\.(19|20|21)[0-9][0-9]$