Xisp

A simple lisp style language. Easy to be parsed in other languages. Xisp works like a USB memory stick that be easily parsed and embedded in any other language.

1. Target

Xisp is developed for sending executable logic across devices, which might be Android or iOS. Xisp is designed short, simple and easy to be parsed. Xisp only deals with basic operators and structures. Any complex things should be implemented by the language who parses Xisp.

2. Grammar

; After a ';', this is comment
(operator, val1, val2, ...) ; returns the result val

2.1 Structures

Constants

1, 2, 3... ; Integer
1.2f       ; Float / Double
{1, 2}     ; Array
0/not 0    ; Boolean
"c"        ; Char
"Strings"  ; String

Operators

! ++ -- ~  ; 1 val operator
+-*/%~><   ; 2 val operator

Functions: Function name should avoid key words, or xisp will stop running. See more in 2.3 Illegal Usage.

(def, f, (+, a, b))  ; Define a function `f(a, b) -> a + b`
(f, 1, 2)            ; Returns 3

OO: . and this is used to interact with OO languages

; with java
(Log.d, "TAG", this.testStr)

2.2 Key words & Usages

Defination: def

   ; Example for 'def'
   (def, a)               ; Assign a val named a
   (def, b, 1)            ; Assign a val named b, and init with 1
   (def, f, (+, a, b))    ; Define a function `f(a, b) -> a + b`, note all unassigned val will be treated as inputs for the function
   ~~~ 

2. Release: `rls`

~~~lisp
   ; Example for 'rls'
   (rls, a)    ; Release val a
   (rls, f)    ; Release function f, the name can be used to other things
   ~~~

3. Loops: `for`

~~~lisp
   ; Example for 'for'
   (for,
     (def, a, 1),  ; a = 1
     (>, a, 10),   ; if a > 10, stop loop
     (++, a)       ; a++ in every loop 
   )
   (rls, a)
   ~~~

4. Conditions: `if`

~~~lisp
   ; Example for 'if'
   (if,
     switch,                     ; if (switch) {
     (=, switch, (~, switch)),   ;    toggle switch
     ()                          ; } else { do nothing }
   )
   ~~~

5. Exceptions: `try`

~~~lisp
(try,
  (def, def),                          ; Try exp  : Try some dangerous things
  (log, "Error: override key words")   ; Catch exp: Do if something is wrong
)

Print: log

(log, "hello world") ; print hello world

2.3 Illegal usages

In all usages in this section, Xisp will stop running and go to the nearest catch exp if avaliable.

Override key words:

(def, def)

Too less inputs:

(+, 1)

Too more inputs:

(+, 1, 1, 1)

Undefined val: