Heaven

Language "Heaven"

# components -> { :red -> 5, :green -> 6, :blue -> 5 }
structure Bitfield( width, storage_type : type@uint! )
    bits := storage_type.bits
    @storage : storage_type = 0
    def mask_of( index: uint )
        assert( index < bits )
        2 ** (bits - index - 1)
    end
    def mask_of( selection: range(uint) )
        assert( selection.within? [0..bits) )
        bmask := mask_of( selection.begin )
        emask := mask_of( selection.end )
    end
    def operator[]( index: uint )
        @storage & mask_of(index)
    end
    def operator[]=( index: uint, value: bool )
        if ( value )
            @storage &= ~mask_of(index)
        else
            @storage |= mask_of(index)
        end
    end
    def operator[]( selection: range(uint) )
        selection.clamp![0..bits)
        if ( selection.inclusive_end? ) then
            shift := bits-selection.end
        else
            shift := bits-selection.end-1
        end
        (@storage & mask_of(selection)) >> shift
    end
end

structure Bitfield( width, storage_type_ : structure? = nil )
    @@storage_type := storage_tpe || if ( width <= 8 )
        Byte
    elsif ( width <= 16 )
        Word
    elsif ( width <= 32 )
        DWord
    elsif ( width <= 64 )
        QWord
    else
        FixedWidthArray( width/8 )
    end
    @storage : @@storage_type = 0
    def operator[]( index: int | range )
        case index
        when int
        when range
        end
    end
end
structure Packed( *components )
    @@width := componets.values.sum
    @data : Bitfield(@@width) = 0
    components.each_index do |i,component,cwidth|
        shift := components(i..).values.sum
        def #{component}();  @data[shift..shift+cwidth) << (8-shift);  end
        def #{component}=( value );  @data[shift..shift+cwidth) = ( value >> (8-shift) ); end
    end
end

Pakced # -> type factory ?
ColorType := Packed( :red->5, :green->6, :blue->5 ) # -> type

Previous Work

A pragmatic language for the future (GDNet Thread)

Outstanding Issues

Range comparisons

Comparison Chaining?

1 <= 2 <= 3 <= 4

operator<= returns rhs if lhs<=rhs, otherwise nil ?
ComparisonResult -> bool && ComparisonResult <= Numeric ?

Comparitive Operator?

1 <=> 2 — :lessthan (ordered), :equal, :inequal (unordered) :greaterthan (ordered)?
(1 <= 2) == (1 <=> 2 != :greaterthan) ?

Range Syntax

[begin..end) [begin..end] (begin..end] (begin..end) ?
begin..end begin…end ?

Globals and dual-stage eval

dirs = Dir[ "fnord/*" ] —- is this relative to the CWD during compile or the CWD during run-eval() init?

Overloading & Multiple Dispatch

Call syntax:
f( a, b, c ) - best-match lookup
f( a:type, b:type, c:type ) - coerceion?
f( a:~type, b:~type, c:~type ) —- base lookup?

Ambiguities:
Stage 1 (compile) eval: Error
Stage 2 (runtime) eval: Diagnose potential type "valleys"? Major reliance on assert()ions?

Pre/post-conditions, assertions

class Array
operator[]( unsigned index )
precondition index < self.size
return …
end
end

Current Work

Literals

0x0123456789ABCDEF[.FFFF]  -- hexadecimal literal
          01234567[.7777]  -- octal literal
       10100011101[.1111]b -- binary literal
        1234567890[.0000]  -- Decimal Literal
                :abdef1234 -- Symbol (deferred on-access lookup)
                 abdef1234 -- Identifier (immediate current-scope lookup)
         "fnord!!:\"aasdf" -- String (localizeable)
                      ???? -- String (unlocalizeable)

Scopes

Build-Time [Global]
Build-Time [Unit]
Function
Class

page_revision: 6, last_edited: 1180568530|%e %b %Y, %H:%M %Z (%O ago)

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