About

28z is a simple VM loosely inspired by the RPL environment on the HP-28 calculator.

Building

go build .

Running

./28z

Data types

Floating point

All values are assumed to be floating point by default.

String

String values are identified by a single preceeding quotation mark (').

Sequence

Sequence values contain a sequence of instructions created dynamically through the define and reduce sequence instructions.

Reference

Reference values are identified by a preceeding dollar sign ($) and are replaced with the corresponding register or variable value either when input, or in storing mode when evaluated.

References can also be specified with a preceeding percent sign (%) in interactive input to have the reference be resolved and immediately evaluated.

Supported instructions

eval

• Description: Evaluate x
• Arg count: 1
• Result count: 0
• Usage:

drop

• Description: Drop x
• Arg count: 1
• Result count: 0
• Usage: drop ⤶

files

• Description: List availabel files in ROM
• Arg count: 0
• Result count: 0
• Usage: files ⤶ [files]⥱Console

>

• Description: Define sequence
• Arg count: 0
• Result count: 0
• Usage: > ⤶

store

• Description: Store y into x, preserving y
• Arg count: 2
• Result count: 1
• Usage: 2 ⤶ 'a ⤶ put ⤶ ⤒2; y⥗a

clear

• Description: Clear stack
• Arg count: 0
• Result count: 0
• Usage: clear ⤶

inspect

• Description: Write a raw object to file
• Arg count: 1
• Result count: 0
• Usage:

render

• Description: Render RAM as buffer
• Arg count: 0
• Result count: 0
• Usage: render ⤶

prompt

• Description: Prompt the user for a value
• Arg count: 1
• Result count: 1
• Usage: 'Enter x ⤶ prompt ⤶

stream

• Description: Apply x to renderable RAM
• Arg count: 1
• Result count: 0
• Usage:

mod

• Description: y modulus by x
• Arg count: 2
• Result count: 1
• Usage: 6 ⤶ 2 ⤶ / ⤶ ⤒0

cos

• Description: cos of x
• Arg count: 1
• Result count: 1
• Usage:

deref

• Description: Derefernce x, replacing x
• Arg count: 1
• Result count: 1
• Usage: 'a ⤶ deref ⤶ ⤒a

pair

• Description: Collect x and y into x
• Arg count: 2
• Result count: 1
• Usage: 1 ⤶ 2 ⤶ collect ⤶ ⤒[2]:1,2

dec

• Description: Decrement the loop register
• Arg count: 0
• Result count: 0
• Usage: dec

apply

• Description: Evalue x against all entries in y to modify y
• Arg count: 2
• Result count: 1
• Usage: apply ⤶

exchange

• Description: Exchange y and the value in var x
• Arg count: 2
• Result count: 1
• Usage: 3 ⤶ 'a ⤶ exchange ⤶ ⤒a 3⥗a

purge

• Description: Purge x
• Arg count: 1
• Result count: 0
• Usage: 'a ⤶ purge ⤶ undefined⥗a

repeat

• Description: Execute x repeatedly
• Arg count: 1
• Result count: 0
• Usage: 0 ⤶ < ⤶'f ⤶ repeat ⤶

inverse

• Description: Inverts x
• Arg count: 1
• Result count: 1
• Usage:

move

• Description: Store y into x
• Arg count: 2
• Result count: 0
• Usage: 2 ⤶ 'a ⤶ asref ⤶ y⥗a

collect

• Description: Collect stack into x
• Arg count: 1
• Result count: 1
• Usage: 1 ⤶ 2 ⤶ collect ⤶ ⤒[2]:1,2

show

• Description: Render and pause
• Arg count: 0
• Result count: 0
• Usage:

>=

• Description: Set the result flag to 1 if y >= x
• Arg count: 2
• Result count: 0
• Usage:

sleep

• Description: Sleep for x ms
• Arg count: 1
• Result count: 0
• Usage:

graph

• Description: Graph a sequence
• Arg count: 3
• Result count: 0
• Usage: graph ⤶

status

• Description: Display status
• Arg count: 0
• Result count: 0
• Usage:

v+

• Description: Addition for all permuations of x and y
• Arg count: 2
• Result count: 1
• Usage:

produce

• Description: Pop from this stack and push to previous
• Arg count: 1
• Result count: 0
• Usage: produce ⤶

<=

• Description: Set the result flag to 1 if y <= x
• Arg count: 2
• Result count: 0
• Usage:

-

• Description: Subtract x from y
• Arg count: 2
• Result count: 1
• Usage: 6 ⤶ 2 ⤶ - ⤶ ⤒4

halt

• Description: Halt execution
• Arg count: 0
• Result count: 0
• Usage: halt ⤶

expand

• Description: Expand x into the stack
• Arg count: 1
• Result count: -1
• Usage: ⤒[2]:1,2 | expand ⤶ ⤒1 ⤒2

print

• Description: Print x
• Arg count: 1
• Result count: 0
• Usage: 'Hello world ⤶ print ⤶ Hello world⥱Console

unset

• Description: Sets the result flat to 0
• Arg count: 0
• Result count: 0
• Usage:

*

• Description: Multiply y by x
• Arg count: 2
• Result count: 1
• Usage: 6 ⤶ 2 ⤶ * ⤶ ⤒12

/

• Description: Divide y by x
• Arg count: 2
• Result count: 1
• Usage: 6 ⤶ 2 ⤶ / ⤶ ⤒3

this

• Description: Refer to the current sequence
• Arg count: 0
• Result count: 1
• Usage: this ⤶

zero

• Description: Zero RAM
• Arg count: 0
• Result count: 0
• Usage:

==

• Description: Set the result flag to 1 if x = y
• Arg count: 2
• Result count: 0
• Usage:

ceval

• Description: Conditionally evaluate x if result flag is 1
• Arg count: 1
• Result count: 0
• Usage: ⤒ | ceval ⤶

end

• Description: Return from function
• Arg count: 0
• Result count: 0
• Usage: end ⤶

clearbuf

• Description: Clear the output buffer
• Arg count: 0
• Result count: 0
• Usage:

mmap

• Description: Map a file to RAM
• Arg count: 1
• Result count: 0
• Usage: 'rom/file.raw ⤶ mmap ⤶ file.byes⥱RAM

sin

• Description: sin of x
• Arg count: 1
• Result count: 1
• Usage:

<

• Description: Define sequence
• Arg count: 0
• Result count: 0
• Usage: < ⤶

each

• Description: Evaluate x against all entries in y
• Arg count: 2
• Result count: 0
• Usage:

setloop

• Description: Set loop counter to x
• Arg count: 1
• Result count: 0
• Usage: 5 ⤶ setloop ⤶

loop

• Description: Execute x if the loop counter is not zero
• Arg count: 0
• Result count: 0
• Usage: 5 ⤶ setloop ⤶ ⤒ | loop ⤶

stop

• Description: Stop the current loop
• Arg count: 0
• Result count: 0
• Usage:

+

• Description: Add x and y
• Arg count: 2
• Result count: 1
• Usage: 6 ⤶ 2 ⤶ + ⤶ ⤒8

rand

• Description: Generate random between 0 and 1
• Arg count: 0
• Result count: 1
• Usage:

reduce

• Description: Use x to reduce y to a single value
• Arg count: 2
• Result count: 1
• Usage: reduce ⤶

swap

• Description: Swap x and y
• Arg count: 2
• Result count: 2
• Usage: swap ⤶ ⤒x,y

dup

• Description: Duplicates x on the stack
• Arg count: 1
• Result count: 2
• Usage:

consume

• Description: Pop from previous stack and push to current
• Arg count: 0
• Result count: 1
• Usage: consume ⤶

enter

• Description: Enter function
• Arg count: 0
• Result count: 0
• Usage: enter ⤶

get

• Description: Dereference x, preserving x
• Arg count: 1
• Result count: 1
• Usage: 'a ⤶ get ⤶ ⤒a

!=

• Description: Set the result flag to 1 if x != y
• Arg count: 2
• Result count: 0
• Usage:

ceval2

• Description: Conditionally evaluate y if result flag is 1, otherwise evaluate x
• Arg count: 2
• Result count: 0
• Usage: ⤒, ⤒ | ceval2 ⤶

generate

• Description: Evaluate a pair where y is the last input and x is the generator
• Arg count: 1
• Result count: 1
• Usage: ⤒ ⤶ generate ⤶ ⤒, ⤒