Robot Calculator, v1.1.0

The electronic calculator.

Support for NaN and infinity values, display the text block aligned vertically by the LCD center, update the dependencies, and perform refactoring.

Change Log

• evaluation:
  • number evaluation:
    • support for special values:
      • support for NaN — NAN as a constant;
      • support for an infinity — INF as a constant;
  • refine the evaluation restrictions;
• components:
  • displaying is made through the character LCD:
    • LCD dimensions are configurable;
• displaying:
  • display the text block of two lines aligned vertically by the center;
  • display an input expression in the first line of the text block, aligned horizontally by the right side;
  • display a result of expression evaluation in the second line of the text block, aligned horizontally by the right side;
• update the dependencies:
  • use the Robot Timer library;
  • use the Robot Button library;
• perform refactoring.

Features

• evaluation:
  • number evaluation:
    • support for a whole number;
    • support for a fractional number:
      • support for a fractional number without a whole part;
      • support for a fractional number without a fractional part;
    • support for special values:
      • support for NaN — NAN as a constant;
      • support for an infinity — INF as a constant;
    • ignore duplicated zeros at the beginning of a number;
    • return NaN:
      • return NaN for an incorrect number;
      • return NaN for a number causing overflow;
    • truncate a number longer than the internal buffer;
  • operation evaluation:
    • supported operations:
      • addition;
      • subtraction;
      • multiplication;
      • division;
    • typo processing:
      • support for several operations in a row:
        • only operations with equal or growing priorities;
        • only the first operation will be used;
      • support for expression starting with an operation:
        • only operations with equal or growing priorities;
        • the leading operation will be ignored;
      • support for expression ending with an operation:
        • only operations with equal priorities;
        • the trailing operation will be ignored;
• components:
  • displaying is made through the character LCD:
    • LCD dimensions are configurable;
  • controls:
    • expression input and evaluation is made through a 4x4 matrix membrane keypad;
    • clearing whole input is made through a separate button;
    • erasing one character is made through a separate button;
• displaying:
  • display the text block of two lines aligned vertically by the center;
  • display an input expression in the first line of the text block, aligned horizontally by the right side;
  • display a result of expression evaluation in the second line of the text block, aligned horizontally by the right side.

Grammar

Grammar in an EBNF:

expression = addition;

addition = multiplication, {("+" | "-"), multiplication};
multiplication = number, {("*" | "/"), number};
number = NUMBER LITERAL | NUMBER CONSTANT;

NUMBER LITERAL = ? /(\d+\.\d*)|(\d*\.\d+)|\d+/ ?;
NUMBER CONSTANT = "NAN" | "INF";

Example of an expression: 1.2+2.3*4.2.