Enum Opcode

pub enum Opcode {
    Literal(Val),
    Push(Rc<str>),
    Pop(Rc<str>),
    PushArr(Rc<str>),
    PopArr(Rc<str>),
    DimArr(Rc<str>),
    EraseArr(Rc<str>),
    IfNot(Address),
    Jump(Address),
    Next(Rc<str>),
    On,
    Return,
    Clear,
    Cls,
    Cont,
    Def(Rc<str>),
    Defdbl,
    Defint,
    Defsng,
    Defstr,
    Delete,
    End,
    Fn(Rc<str>),
    Input(Rc<str>),
    LetMid,
    List,
    Load,
    LoadRun,
    New,
    Print,
    Read,
    Renum,
    Restore(Address),
    Save,
    Stop,
    Swap,
    Troff,
    Tron,
    Neg,
    Pow,
    Mul,
    Div,
    DivInt,
    Mod,
    Add,
    Sub,
    Eq,
    NotEq,
    Lt,
    LtEq,
    Gt,
    GtEq,
    Not,
    And,
    Or,
    Xor,
    Imp,
    Eqv,
    Abs,
    Asc,
    Atn,
    Cdbl,
    Chr,
    Cint,
    Cos,
    Csng,
    Date,
    Exp,
    Fix,
    Hex,
    Inkey,
    Instr,
    Int,
    Left,
    Len,
    Log,
    Mid,
    Oct,
    Pos,
    Right,
    Rnd,
    Sgn,
    Sin,
    Spc,
    Sqr,
    Str,
    String,
    Tab,
    Tan,
    Time,
    Val,
}

Virtual machine instruction set

The BASIC virtual machine has no registers. Every operation is performed on the stack.

For example: LET A=3*B compiles to [Literal(3), Push(B), Mul, Pop(A)]

See https://en.wikipedia.org/wiki/Reverse_Polish_notation

Variants

Literal(Val)

Push literal value on to the stack.

Push(Rc<str>)

Push stack value of named variable. Infallible.

Pop(Rc<str>)

Pop stack value to named variable. This is the LET statement and may generate errors.

PushArr(Rc<str>)

PopArr(Rc<str>)

DimArr(Rc<str>)

EraseArr(Rc<str>)

IfNot(Address)

Pop stack and branch to Address if not zero.

Jump(Address)

Unconditional branch to Address.

Next(Rc<str>)

Process the FOR loop on the stack.

On

ON x GOTO/GOSUB lines

Return

Expect Return(Address) on stack or else error: RETURN WITHOUT GOSUB. A single assignable value before the Return(Address) will be restored to the stack. Branch to Address.

Clear

Cls

Cont

Def(Rc<str>)

Defdbl

Defint

Defsng

Defstr

Delete

End

Fn(Rc<str>)

Input(Rc<str>)

LetMid

List

Load

LoadRun

New

Print

Read

Renum

Restore(Address)

Save

Stop

Swap

Troff

Tron

Neg

Pow

Mul

Div

DivInt

Mod

Add

Sub

Eq

NotEq

Lt

LtEq

Gt

GtEq

Not

And

Or

Xor

Imp

Eqv

Abs

Asc

Atn

Cdbl

Chr

Cint

Cos

Csng

Date

Exp

Fix

Hex

Inkey

Instr

Int

Left

Len

Log

Mid

Oct

Pos

Right

Rnd

Sgn

Sin

Spc

Sqr

Str

String

Tab

Tan

Time

Val

Trait Implementations

impl Clone for Opcode

fn clone(&self) -> Opcode

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Opcode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Opcode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.