Structure of A Lex File
The structure of a Lex file is intentionally similar to that of a yacc file; files are divided into three sections, separated by lines that contain only two percent signs, as follows:
Definition section %% Rules section %% C code section- The definition section defines macros and imports header files written in C. It is also possible to write any C code here, which will be copied verbatim into the generated source file.
- The rules section associates regular expression patterns with C statements. When the lexer sees text in the input matching a given pattern, it will execute the associated C code.
- The C code section contains C statements and functions that are copied verbatim to the generated source file. These statements presumably contain code called by the rules in the rules section. In large programs it is more convenient to place this code in a separate file linked in at compile time.
Read more about this topic: Lex (software)
Famous quotes containing the words structure of, structure and/or file:
“Women over fifty already form one of the largest groups in the population structure of the western world. As long as they like themselves, they will not be an oppressed minority. In order to like themselves they must reject trivialization by others of who and what they are. A grown woman should not have to masquerade as a girl in order to remain in the land of the living.”
—Germaine Greer (b. 1939)
“A committee is organic rather than mechanical in its nature: it is not a structure but a plant. It takes root and grows, it flowers, wilts, and dies, scattering the seed from which other committees will bloom in their turn.”
—C. Northcote Parkinson (1909–1993)
“While waiting to get married, several forms of employment were acceptable. Teaching kindergarten was for those girls who stayed in school four years. The rest were secretaries, typists, file clerks, or receptionists in insurance firms or banks, preferably those owned or run by the family, but respectable enough if the boss was an upstanding Christian member of the community.”
—Barbara Howar (b. 1934)