moo/moo/README.md

Top-level elements

• #include
• #pragma
• class
• interface
• pooldic

Comments

#! comment text
// comment text
/* comment text */

Literal notations

• 200 decimal integer

• 2r1100 binary integer

• 16rFF00 hexadecimal integer

• 20p9999.99 fixed-point decimal where 20 is the number of digits after the point

• 999.9 fixed-point decimal

• $X character

• C'X' -> charcter??

• C"X" -> character??

• 'XXXX' string literal

• "XXXX" string litearl with escaping

• B'XXXXXX' -> byte array literal

• B"XXXXX" -> byte array literal with escaping

• #XXXX symbol

• #'XXXX' quoted symbol

• #"XXXX" quoted symbol with escaping

• #\e123 Error literal

• #\pB8000000 SmallPointer(smptr) literal

• #() Array. Comma as element delimiter is optional

• #[] ByteArray. Comma as element delimiter is optional #[ 16r10, 16r20, 16r30 ] #[ "\x10\x20", "\x30" ]

• #{} Dictionary - not supported yet

The followings are not literals. The followings forms expressions.

• ##() Array expression. Comma required to delimit elements
• ##[] ByteArray expression. Comma required to delimit elements
• ##{} Dictionary expression. Comma required to delimit elements

The followings are not implemented. but can i do something like these?

• S#[] String literal with each character specified. S%{A B C '\n'}
• S#{} String with dynamic expression
• S#{ 65 asCharacter, 64 asCharacter }

Class

class MyClass(Object)
{
	method show: this
	{
	}
}

Class attributes

The word class can be followed by attribute list enclosed in parenthesis. e.g.) class(#limited,#immutable)

• #limited - not instantiable with new.
• #immutable - instantiated object to be read-only.
• #final - disallow subclasses.
• #uncopyable - instantiated object not to be copied.
• #byte, #character, #halfword, #word, #liword, #pointer - specify the type of a non-pointer object. a non-pointer type can have an additional size enclosed in parenthesis. e.g.) #character(2) a non-pointer object is not allowed to have named instanced variables. a non-pointer object is always variable indexed.
• #pointer - specify a pointer variable indexed object. an instantiate object can have extra object pointers in additon to named instance variables.

class(#word(2)) X(Object) { } 
X new -> create an object with 2 words.
X new: 4 -> create an object with 6 words.

if an object is asked to instantiate with trailer in the class defintion, it becomes uncopyable, without the #uncopyable attribute.

class Shader(Object) from 'shader'
{
// if the shaer module calls moo_setclasstrsize(), an instance of Shader is uncopyable
}

Pool dictionary

pooldic MyData
{
	A := 20,
	B := 30,
	C := 40
}

class MyClass(Object)
{
	import MyData.

	method x ()
	{
		MyData.A dump.
		C dump. // if imported, it doesn't require prefixing with MyData.
	}
}


class MyClass2(Object)
{
	pooldic Const
	{
		A := 20,
		B := 30
	}

	method x()
	{
		A dump. // the nested pooldic is auto-imported.
		Const.A dump.
		self.Const dump.
	}
}

class MyClass3(MyClass2)
{
	pooldic Const
	{
		A := MyClass2.Const.A // pooldic is not inherited. need redefinition for auto-import
		B := MyClass2.Const.B
	}
}

class MyClass4(MyClass2)
{
	import MyClass2.Const. // similar to redefinition inside the class. it won't be available MyClass4.Const as such is not available.


	method x 
	{
		MyClass2.Const at: #XXX put: 'QQQQQQQQQQQQQQ'. // you can add a new item dynamically,
		(MyClass2.Const at: #XXX) dump. // and can access it.

		// the compiler doesn't recognize the dynamically added item as MyClass2.Const.XXX
	}
}

Flow Control

k := if (i < 20) { 30 } else { 40 }.

if (a < 10) { ... }
elif (a < 20) { ... }
else { ... }.

ifnot (i < 20) { 30 } else { 40 }. /* TODO: ifnot or nif? elifnot or elnif? */

if (a < 10) { .. } 
elifnot (a > 20) { ... }
else { ... }.

while (true)
{

}.

until (a > b)
{
}.

do
{
} while (a > b).

do
{
} until (a > b).

[a > b] whileTrue: [ ... ].
[a > b] whileFalse: [ ... ].

1 to: 20 do: [:count | ... ].
1 to: 10 by: 3 do: [:count | ... ].
30 timesRepeat: [ ... ].

Exception handling

Exception signal. Exception signal: "message".

[ ... ] on: Exception do: [:ex | ... ].

ex retry. ex resume. ex resume: value. ex return: value.

return from context(method/block)

explicit return operators

^ return_stacktop
^^ local_return

implicit return when the end of the context is reached

• a method context returns the receiver.
• a block context returns the last evaluated value. if nothing has been evaluated, nil is returned.

goto

goto jump_label.

jump_label:
	a + b.

goto inside a block context.

[ 1 + 2. goto r. 3 + 4. r: 99 ]

goto must not cross the boundary of the block context.

this is invalid. cannot jump into a block from outside 
and vice versa.
 goto x.
 [ x:
   1 + 2 ].

Type checking

Type checking not implemented yet.

class SampleClass(Object)
{
	method run => Integer
	{
	}

	method execute((Integer)a,(Integer)b) => Integer
	{
	}

	method handle: (Object)this with: (a Integer)care => Integer
	{
	}
}

TODO: How to specify return type of a block? or How to specify parameter type to a block? How to evaluate a block type-safely?

[ :(Integer)a :(Integer)b => Integer | 
	| (Integer)c (Integer)d }
	a + b 
] with: 20 with: 10

the method value is a variadic method. and it is a primitive.
[ :a :b | a + b ](1, 20) <---- syntax sugar for [:a :b | a + b] value(1, 20).

[:(Integer)a :(Integer)b => Integer | a + b ] value("kkkk", 20) 
 -> the first argument violates the expected type.
 -> argument types to a method is defined in the method signature.
 -> but the block argument types are specified in the block itself.
 -> so it doesn't seem natural to achieve type safety without treating 'value' specially.
 -> create a shorthand expression for 'value' [:(Integer)a :(Integer)b => (Integer) | a + b ](1, 2)
 -> ] followed by ( ===> shorthand expression for value.
 -> it looks more sensible to treat this () specially
 
what looks better as a shorthand expression for block value?
 [ :a :b | a + b ](10, 20)
 [ 10 + 20 ]() // no arguments
 [ :a :b | a + b ]->(10, 20). // -> cannot form a valid binary selector. must exclude it from binary selector patterns
 [ 10 + 20 ]->() // if no arugments are required.
 
 continuation?
 | a |
 a->()? block value?
 
 | (Block)a |
 a->()? block value?
 

FFI

	ffi := FFI new: 'libc.so.6'.
	[
		(ffi call: #printf signature: 's|sl>i' arguments: #("[%s ffi test %ld]\n" "sloppy" 12345678)) dump.
		(ffi call: #printf signature: 's>i' arguments: #("[%% ffi test %%]\n")) dump.
		(ffi call: #puts signature: 's>i' arguments: #("this is ffi test")) dump.
		(ffi call: #time signature: 'p>l' arguments: #(#\p0)) dump.
	]
	ensure: [
		ffi close.
	].

Command line options

moo --log /dev/stderr ../kernel/test-001.moo
moo --log /dev/stderr,warn+ ../kernel/test-001.moo