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Perl Compatible Regular Expressions (PCRE) is a library written in C, which implements a regular expression engine, inspired by the capabilities of the Perl programming language. Philip Hazel started writing PCRE in summer 1997. [ 3 ]
When an assertion failure occurs, the programmer is immediately notified of the problem. Many assertion implementations will also halt the program's execution: this is useful, since if the program continued to run after an assertion violation occurred, it might corrupt its state and make the cause of the problem more difficult to locate.
In computer software testing, a test assertion is an expression which encapsulates some testable logic specified about a target under test. The expression is formally presented as an assertion, along with some form of identifier, to help testers and engineers ensure that tests of the target relate properly and clearly to the corresponding specified statements about the target.
The assert macro implements runtime assertion. If the expression within it is false, the macro will print a message to stderr and call abort(), defined in stdlib.h.The message includes the source filename and the source line number from the macros __FILE__ and __LINE__, respectively. [2]
A regular expression (shortened as regex or regexp), [1] sometimes referred to as rational expression, [2] [3] is a sequence of characters that specifies a match pattern in text. Usually such patterns are used by string-searching algorithms for "find" or "find and replace" operations on strings , or for input validation .
Logical assertion, a statement that asserts that a certain premise is true; Proof by assertion, an informal fallacy in which a proposition is repeatedly restated; Time of assertion, in linguistics a secondary temporal reference in establishing tense; Assertive, a speech act that commits a speaker to the truth of the expressed proposition
A common use for an expression index is to support case-insensitive searching or constraints. For example, if a web site wants to make user names case-insensitive, but still preserve the case as originally entered by the user, an index can be created on the lower-case representation of the user name:
The validity of an inference depends on the form of the inference. That is, the word "valid" does not refer to the truth of the premises or the conclusion, but rather to the form of the inference. An inference can be valid even if the parts are false, and can be invalid even if some parts are true.