elise-lang

ToDo

• number
• print function
• basic arithmetics
• value binding
• nil
• boolean
• strings
• conditions
• nil? function
• custom function
• add source code to error message with error highlighting
  • lexer
  • parser
  • semanalyzer (static)
  • interpreter
• disallow to define identifiers with the name of known function (add, sum, nil? etc.)
• function closure (use data from lexical scope during function execution)
• runtime optimizations (get rid of redundant allocations)

Boolean

Boolean literals: true and false

String

Use " to create string literals. Example:

"Hello, World"
"Hello\nWorld"

Number

Number literals: 1, 1.2

.print

Prints result of expressions

.print(& more)

.println

Like .print but with \n at the end

.println(& more)

.add

Returns the sum of numbers. .add() returns 0

.add()
.add(x)
.add(x y)
.add(x y & more)

.sub

If no ys are supplied, returns the negation of x, else subtracts the ys from x and returns the result

.sub(x)
.sub(x y)
.sub(x y & more)

.mul

Returns the product of nums. .mul() returns 1

.mul()
.mul(x)
.mul(x y)
.mul(x y & more)

.div

If no denominators are supplied, returns result of 1/numerator, else returns numerator divided by all of the denominators

.div(x)
.div(x y)
.div(x y & more)

.let

Evaluates the exprs in a lexical context in which the symbols in the binding-forms are bound to their respective init-exprs

.let([binding-form init-expr] exprs*)

Example:

.let([x 2, y 10]
    .println(.add(x y)))

Also, .let function returns the result of the last expression:

.print(.let([x 1] x))

Result: 1

.greatr

Returns true if nums are in monotonically decreasing order, otherwise false.

.greatr(x)
.greatr(x y)
.greatr(x y & more)

.greatr-eq

Returns true if nums are in monotonically non-increasing order, otherwise false.

.greatr-eq(x)
.greatr-eq(x y)
.greatr-eq(x y & more)

.less

Returns true if nums are in monotonically increasing order, otherwise false.

.less(x)
.less(x y)
.less(x y & more)

.less-eq

Returns true if nums are in monotonically non-decreasing order, otherwise false.

.less-eq(x)
.less-eq(x y)
.less-eq(x y & more)

.eq

Equality. Returns true if x equals y, false if not.

.eq(x)
.eq(x y)
.eq(x y & more)

.not

Returns true if x is logical false, false otherwise.

.not(x)

.not-eq

Same as .not(.eq(x)).

.not-eq(x)
.not-eq(x y)
.not-eq(x y & more)

.and

Evaluates exprs one at a time, from left to right. If a form returns logical false (nil or false), .and returns that value and doesn't evaluate any of the other expressions, otherwise it returns the value of the last expr. .and() returns true.

.and()
.and(x)
.and(x & next)

.or

Evaluates exprs one at a time, from left to right. If a form returns a logical true value, .or returns that value and doesn't evaluate any of the other expressions, otherwise it returns the value of the last expression. .or() returns nil.

.or()
.or(x)
.or(x & next)

.bool

Coerce to boolean. Everything except false and nil is true in boolean context.

.bool(x)

.if

Evaluates the first argument and performs boolean coercion of the result. If it results to true evaluates the second argument and returns result. Otherwise, evaluates the third argument and returns the result. If the third argument is absent - returns nil.

.if(condition then)
.if(condition then else)

.nil?

Returns true if x is nil, false otherwise

.nil?(x)

.fn

.fn (name [& args] body)

Creates an identifier labeled with name that holds a function declaration record that can be invoked with args (if declared) to execute its body. Body has access to args identifiers that are bound to the values passed during invocation as well as identifiers in outer (parent) scope where it's created. Function can be invoked only after declaration.

Example:

.fn (fact [n]
    .if(.eq(n, 0)
      1
      .mul(n, .fact(.sub(n 1)))))

.println(.fact(3))