GLOSSARY

Bison GNU Project parser generator, a yacc replacement.

CFG Context-free grammar, most of the present day programming languages can be specified in terms of such a grammar.

DFA Deterministic finite-state automaton, see Appendix A.

Flex Fast lexical analyzer generator, a lex replacement.

GCC GNU compiler collection, developed by GNU project as a free compiler for GNU system. Front ends: C, C++, Objective-C, Fortran, Java, Ada and recently some other languages.

Generator Any entity that produces an effect or is responsible for events or results; specifically a software device to produce a sequence of output obeying certain specifications.

Intermediate Between the front- and back-ends of a compiler.

Interpreter A program that translates and executes source language statements one line at a time.

Lex A lexical analyzer generator, originating on Unix O/S.

Lexical Related to words, basic language elements.

Parse Analyze syntactically by assigning a structure making up a sentence (statement).

Parser A computer program that divides code up into functional components, i.e. does parsing.

Patterns Convention, normal, rule and formula, specifically the arrangements of characters according to specified rules.

Python An interpreted, interactive and object-oriented programming language.

Regular Expression Conforming to a standard or pattern, specifically a way of specifying simple and least complex languages and a way of specifying Chomsky Level 3 languages.

Regular Grammar Grammar which generates a regular language.

Regular Language A simple and least complex language, Chomsky Level 3 language.

Scanner A lexical analyzer; it systematically scans the input from one end to another and identifies “words” or basic language elements.

Semantic Related to the meaning of a group of sentences.

Syntax A systematic orderly arrangement, sentence structure and the grammatical arrangement of words in sentences.

Token Something serving as a representative of something else; specifically internal representation, usually an integer, for a particular language element.

Tree A data structure; examples of uses are a parse tree, syntax tree and Abstract Syntax Tree (AST).

Yacc “Yet another compiler compiler”, a compiler writing tool first used in Unix O/S.

Actions The technical meaning is: the action taken when a particular syntactic construct is detected, effectively implements the “meaning” of the construct.

Associativity A property of a binary operator, which says that within an expression containing two or more occurrences of the same operator, the order in which the operations are performed does not matter as long as the sequence of the operands is not changed.

Concatenation The linking together of a consecutive series of symbols. gcc GNU C compiler.

Keyword A significant word used in indexing or cataloging, but in programming languages it means that a word which has a particular well-defined role in the syntax of the language; the keywords are generally reserved words.

Label An identifier used for specifying a particular sentence in a program.

Lexer See Scanner.

Lookahead Taking a parsing decision for the current input symbol, based on the next symbol which will be subsequently scanned.

Match A positive result of comparison of the input string and a pattern.

Precedence The order of operations is a rule used to unambiguously specify which operations should be performed first in a given mathematical expression.

Recovery Arriving at a well-defined and valid state, after an error is detected while performing lexical or syntax analysis; the idea is that it should be possible, after the recovery, that as much as of the rest of the code can be analyzed.