numbers.ne

# Paste this into https://omrelli.ug/nearley-playground/

main -> expression {% id %}

expression ->
  mult_term {% id %}
  | expression _ ("+"|"-") _ mult_term {% d => d[2][0] === '+' ? d[0] + d[4] : d[0] - d[4] %}

mult_term ->
  exp_term {% id %}
  | mult_term _ ("*"|"/") _ exp_term {% d => d[2][0] === '*' ? d[0] * d[4] : d[0] / d[4] %}

exp_term ->
  number_or_fn {% id %}
  | exp_term _ ("^"|"**") _ number_or_fn {% d => Math.pow(d[0], d[4]) %}

number_or_fn ->
  number {% id %}
  | "pi" {% () => Math.PI %}
  | "e" {% () => Math.E %}
  | "ln" _ "(" _ number_or_fn _ ")" {% d => Math.log(d[4]) %}
  | "pow" _ "(" _ number_or_fn _ "," _ number_or_fn _ ")" {% d => Math.pow(d[4], d[8]) %}

number ->
  ("-"|"+") _ number {% d => d[0][0] === '-' ? -d[2] : d[2] %}
  | unsigned_number {% id %}

unsigned_number ->
  unsigned_decimal {% id %} # 123, 1.5
  | hex_number {% id %} # 0xff
  | octal_number {% id %} # 0o77

unsigned_decimal ->
  unsigned_int {% id %} # 123
  | unsigned_int "." unsigned_int {% d => +`${d[0]}.${d[2]}` %} # 1.2

hex_number -> 
  "0x" [a-f0-9]:+ {% d => parseInt(d[1].join(''), 16) %}
  | "0x" [a-f0-9]:+ "." [a-f0-9]:+ {% d => parseInt(d[1].join(''), 16) %}
octal_number -> "0o" [0-7]:+ {% d => parseInt(d[1].join(''), 8) %}
unsigned_int -> [0-9]:+ {% d => +d[0].join('') %}

# Optional whitespace
_ -> [\s]:* {% () => null %}