• baud rate: 115200
• no parity
• 1 stop bit

• $LITERAL := $DECIMAL | $BOOL
• $DECIMAL
  • decimal number
  • examples: 0, 100, 224, -130, 4457
• $BOOL := true | false

• $ID
  • a string whose first character is not captal (not 'A' to 'Z')
  • excludes "true" and "false"

• $TID
  • a string whose first character is captal ('A' to 'Z')

• $PRIM := Int | Bool | $PRIM_LIST | $PRIM_TUPLE
• $PRIM_LIST := '( $PRIM )
• $PRIM_TUPLE := [ $PRIM+ ]

• $TYPE := Int | Bool | $TYPE_LIST | $TYPE_TUPLE | $TYPE_FUN | $TYPE_DATA
• $TYPE_LIST := '( $TYPE )
• $TYPE_TUPLE := [ $TYPE+ ]
• $TYPE_DATA := $TID | ( $TID $PRIM* )
• $TYPE_FUN := ( $EFFECT ( -> $TYPES $TYPE ) )
• $EFFECT := Pure | IO
• $TYPES := $TYPE | ( $TYPE* )

examples:

'(Int)
[Int Bool]
(Pure (-> (Int INT) Bool))
'('(Int Bool))
[Int Int '([Int Bool])]

• $DATA := ( data $DATA_NAME $MEMBER* )
• $DATA_NAME := $TID | ( $TID $ID* )
• $MEMBER := $TID | ( $TID $PRIM* )

examples:

(data Dim2
  (X Int)
  (Y Int))

(data (Maybe t)
    (Just t)
    Nothing)

• $DEFUN := ( $HEAD_DEFUN $ID ( $ID* ) $TYPE_FUN $EXPR )
• $HEAD_DEFUN := export | defun

• $EXPR := $LITERAL | $ID | $LET | $IF | $MATCH | $LIST | $TUPLE | $APPLY

• $LET := ( let ( $DEFVAR+ ) $EXPR )
• $DEFVAR := ( $LETPAT $EXPR )
• $LETPAT := $ID | [ $LETPAT ]

• $IF := ( if $EXPR $EXPR $EXPR )

• $LIST := '( $EXPR* )

• $TUPLE := [ $EXPR+ ]

• $MATCH := ( match $EXPR $MBODY+ )
• $MBODY := ( $PATTERN $EXPR )
• $PATTERN := _ | $LITERAL | $ID | [ $PATTERN+ ] | ( $TID $PATTERN+ )

• cons: (-> (T '(T) '(T))
• car: (-> '(T) (Maybe T))
• cdr: (-> '(T) (Maybe '(T)))
• nth: (-> (Int [T]) (Maybe T))
• nth: (-> (Int '(T)) (Maybe T))