1. Pattern matching
2. the act of checking for the presence of the constituents of a pattern
3. LEXICAL ANALYSIS
3.1. Lexycal Analyzer Functions:
3.1.1. Remove white spaces and comments form skeleton source program.
3.1.2. Keep track of line numbers
3.1.3. Produce a sequence of atomic unit called token
3.2. Implementation and Role
3.2.1. Scanner
3.2.1.1. Encode within it information on the possible sequences of characters that can be contained within any of the tokens
3.2.2. Evaluator
3.2.2.1. Goes over the characters of the lexeme to produce a value
3.3. What is?
3.3.1. Lexical analysis is the processing of an input sequence of characters (source code) to produce a sequence of symbols called “lexical tokens”, or just tokens as output
4. LEXEME
4.1. Abstract unit of morphological analysis in linguistics
4.2. In compiler: “A lexeme is a sequence of character in program that is matched by pattern for a token.”
5. PATTERN
5.1. pattern is a rule describing the set of lexeme that represent particular token.
5.2. Pattern Recognition
5.2.1. detection of underlying patterns
6. SOURCE CODE
6.1. What is?
6.1.1. Series of statements written in some human-readable computer programming language
6.2. What for?
6.2.1. Source code is primarily either used to produce object code
6.2.2. Used for the description of software
6.2.3. As a communication tool between experienced programmers
6.3. Licensing
6.3.1. Free
6.3.1.1. the source code is free to use, distribute, modify and study
6.3.2. Privacy
6.3.2.1. source code is kept secret, or is privately owned and restricted
6.4. Quality
6.4.1. General syntactic criteria
6.4.1.1. Readability
6.4.1.2. Writeability
6.4.1.3. Ambiguity
6.4.1.4. Verifiability
6.4.2. Syntactic elements
6.5. Structure
6.5.1. Lexical
6.5.1.1. In this level programs are considered as different groups of strings that make sense.
6.5.2. Syntactic
6.5.2.1. describes the way that program statements are constructed from tokens
6.5.3. Contextual
6.5.3.1. the ‘context’ in which program statements usually contain identifier whose value is dictated by earlier statements
6.5.4. Semantic
7. TOKEN
7.1. What is?
7.1.1. “A lexical tokens / tokens are a sequence of characters that can be treated as a unit in the grammar of the programming languages.”
7.2. Examples
7.2.1. Type Token Punctuation Symbols Alphabetic
7.3. Attribute
7.3.1. Pointer to the symbol table