Step by Step solution about How to resolve the algorithm Literals/Floating point step by step in the Python programming language

Lexical Analysis with Lex

This code defines the lexical grammar for a simple floating-point number type in Lex. It can recognize and tokenize floating-point numbers in various formats.

FLOAT Production:

• The FLOAT production defines the rules for a floating-point number. It has three sub-rules:
  • A decimal point (.) followed by one or more digits, optionally followed by an exponent.
  • One or more digits, followed by a decimal point and an exponent.
  • One or more digits, followed by a decimal point and optionally more digits, followed by an exponent.

DIGITS Production:

• DIGITS matches one or more digits ('0' to '9').

Exponent Production:

• Exponent matches the exponent part of the floating-point number, which consists of the letter 'e' or 'E', followed by an optional sign ('+' or '-'), and one or more digits.

Example Floating-Point Numbers:

• 2.3: Matches the rule 1: decimal point followed by digits.
• .3: Matches the rule 2: digits followed by a decimal point.
• .3e4: Matches the rule 3: digits followed by a decimal point and an exponent.
• .3e+34: Matches the rule 3: digits followed by a decimal point, more digits, and an exponent with a positive sign.
• .3e-34: Matches the rule 3: digits followed by a decimal point, more digits, and an exponent with a negative sign.
• 2.e34: Matches the rule 3: digits followed by a decimal point and an exponent. Note that the leading zero before the decimal point is not required.

FLOAT
    :   '.' DIGITS (Exponent)?
    |   DIGITS '.' Exponent
    |   DIGITS ('.' (DIGITS (Exponent)?)? | Exponent)
    ;

DIGITS : ( '0' .. '9' )+ ;

Exponent
    :    ('e' | 'E') ( '+' | '-' )? DIGITS
    ;


2.3    # 2.2999999999999998
.3     # 0.29999999999999999
.3e4   # 3000.0
.3e+34 # 2.9999999999999998e+33
.3e-34 # 2.9999999999999999e-35
2.e34  # 1.9999999999999999e+34