INTERCAL-64

What it is

INTERCAL-64 extends the 1972 language to 64-bit arithmetic, adds a complete system library written in pure INTERCAL, and ships with the first interactive debugger the language has ever had. The reference compiler is churn; the file extension is .ic64.

Every classic INTERCAL program still compiles and runs unchanged. Nothing has been taken away — only added, and only at widths nobody asked for.

Variables

All classic variable types are supported, joined by three new 64-bit types.

Prefix	Name	Width	Description
.	spot	16-bit	A 16-bit unsigned integer
:	two-spot	32-bit	A 32-bit unsigned integer
::	double cateye	64-bit	A 64-bit unsigned integer
,	tail	16-bit	A 16-bit array
;	hybrid	32-bit	A 32-bit array
;;	double hybrid	64-bit	A 64-bit array

The spot (.) and two-spot (:) retain their classic meanings. The new double cateye (::) extends the series to 64-bit precision. It is so named because it consists of two two-spots, and two twos is four.

Constants

Constants are formed with the mesh (#) prefix.

Prefix	Name	Width
#	mesh	16-bit
##	fence	32-bit
####	stockade	64-bit

The absence of a triple mesh (###) is intentional. Three meshes would imply 48-bit precision, which is not a thing.

Operators

The five original operators are retained without change.

Operator	Name	Type	Description
$	big money	Binary	Interleaves the bits of two operands (mingle)
~	select	Binary	Extracts bits using a mask
&	ampersand	Unary	AND of adjacent bit pairs
V	V	Unary	OR of adjacent bit pairs
?	what	Unary	XOR of adjacent bit pairs

Mingle and select at higher widths

The mingle operator ($) produces a result twice the width of its operands.

Operands	Result
16-bit $ 16-bit	32-bit
32-bit $ 32-bit	64-bit
64-bit $ 64-bit	128-bit (ephemeral)

The 128-bit result of mingling two 64-bit values is ephemeral: it cannot be stored in any variable. It exists only long enough to be consumed by a select (~), which reduces it back to at most 64 bits. Briefly real, then gone — much like a good idea in a committee meeting.

Statements

All original INTERCAL statements are retained without modification. The programmer may continue to ABSTAIN FROM CALCULATING, COME FROM unexpected places, and GIVE UP at any time.

For what COME FROM can do that DO NEXT cannot — including a formal proof that it is computationally necessary — see the papers.

Labels

Labels have been extended to 64 bits, so that programs exceeding 119 lines are assured of enough labels. The reader is aware that 64-bit values take more space. Users are encouraged to avoid labels like (10) DO <whatever> and to prefer (744073709551615) DO <whatever>, in the hope of fewer integration problems in the future. The authors tested the label 744073709551615 but did not test all labels available.