Search results
Results From The WOW.Com Content Network
sed scripts can have comments (the line starting with the # symbol). The s (substitute) command is the most important sed command. sed allows simple programming, with commands such as q (quit). sed uses regular expressions, such as .* (zero or more of any character).
In logic, a set of symbols is commonly used to express logical representation. The following table lists many common symbols, together with their name, how they should be read out loud, and the related field of mathematics.
Regular expressions entered popular use from 1968 in two uses: pattern matching in a text editor [9] and lexical analysis in a compiler. [10] Among the first appearances of regular expressions in program form was when Ken Thompson built Kleene's notation into the editor QED as a means to match patterns in text files.
distance: |, denoting the shortest distance between point to line , so line | is perpendicular to line divisibility : a ∣ b {\displaystyle a\mid b} , read " a divides b " or " a is a factor of b ", though Unicode also provides special 'divides' and 'does not divide' symbols (U+2223 and U+2224:∣, ∤) [ 2 ]
This ensures that the line of tokens conform to the formal grammars of the programming language. The parsing stage itself can be divided into two parts: the parse tree , or "concrete syntax tree", which is determined by the grammar, but is generally far too detailed for practical use, and the abstract syntax tree (AST), which simplifies this ...
The detailed semantics of "the" ternary operator as well as its syntax differs significantly from language to language. A top level distinction from one language to another is whether the expressions permit side effects (as in most procedural languages) and whether the language provides short-circuit evaluation semantics, whereby only the selected expression is evaluated (most standard ...
The shebang line is usually ignored by the interpreter, because the "#" character is a comment marker in many scripting languages; some language interpreters that do not use the hash mark to begin comments still may ignore the shebang line in recognition of its purpose.
If the first character of a line, including indentation, is an asterisk (*) the whole line is considered as a comment, while a single double quote (") begins an in-line comment which acts until the end of the line. ABAP comments are not possible between the statements EXEC SQL and ENDEXEC because Native SQL has other usages for these characters.