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maayanshani,rotem.garti 319111886,207869520

Regular Expressions Used in the Code

1. VARIABLE_NAME_REGEX

Regular Expression: (?!true$)(?!false$)([a-zA-Z]|[a-zA-Z0-9])[a-zA-Z0-9]*

Explanation: This regex defines the structure of a valid variable name.

  • (?!true$)(?!false$): Negative lookahead assertions ensure the variable name is not "true" or "false". This prevents the use of boolean literals as variable names.
  • ([a-zA-Z]|_[a-zA-Z0-9]): Matches a valid starting character for a variable name:
    • [a-zA-Z]: Allows variable names to start with a letter.
    • |: OR operator.
    • _[a-zA-Z0-9]: Allows variable names to start with an underscore followed by an alphanumeric character.
  • [a-zA-Z0-9_]*: Matches the rest of the variable name, allowing any combination of alphanumeric characters and underscores.

Purpose: This ensures variable names:

  • Follow valid naming conventions.
  • Avoid conflicts with reserved boolean literals (true, false).
  • Allow underscores and alphanumeric characters.

2. singleDeclaration

Regular Expression: (" + VARIABLE_NAME_REGEX + ")\s*(=\s*(" + typeValueRegex + "|" + VARIABLE_NAME_REGEX + "))?

Explanation: This regex defines the structure of a valid single variable declaration:

  • (" + VARIABLE_NAME_REGEX + "): Matches the variable name using the rules defined in VARIABLE_NAME_REGEX.
    • Group 1 captures the variable name.
  • \s*: Matches optional whitespace after the variable name.
  • (=\s*(" + typeValueRegex + "|" + VARIABLE_NAME_REGEX + "))?: Matches an optional assignment:
    • =: The assignment operator.
    • \s*: Matches optional whitespace around the assignment operator.
    • (" + typeValueRegex + "|" + VARIABLE_NAME_REGEX + "): Matches the assigned value:
      • typeValueRegex: Valid literal values for the type (int, double, Sring, char, boolean).
      • VARIABLE_NAME_REGEX: Another valid variable name being assigned.
    • Group 3 captures the value being assigned.
    • ?: Makes the assignment optional, allowing for declarations without initialization (e.g., int x;).

Purpose: This regex validates and parses single variable declarations, ensuring:

  • Variable names are valid.
  • Assignments, if present, use either a valid literal value or a valid variable name.
  • Formatting is flexible with optional whitespace.

These regular expressions form the backbone of variable validation and declaration parsing in the program, ensuring adherence to strict syntax rules while maintaining flexibility in formatting.