|:: documentation for NILS Form|
    :@doc string: 
"Nova In-Language Static Form is a possible structure for lowering
Nova code into a bytecode language describable in Nova. This is not
intended to be written by hand."

|:: match $stack $arity :failed:?|
|:: match $stack $symbol|
    :@jet:
"
local s = stacks[$stack]
local s_top = s.n
local tuple = s[s_top]
if not tuple or tuple[1] ~= $symbol then
    push("failed", { })
else
    pop($stack)
    push($stack .. " (r)", { $symbol })
end
"

|:: bind $stack $symbol :failed:?|
|:: bind $stack $register|
    :@jet:
"
local s = stacks[$stack]
local s_top = s.n
local r = stacks[$register]
local r_top = r.n
local s_tuple = s[s_top]
local r_tuple = r[r_top]
if not s_tuple or r_tuple and s_tuple[1] ~= r_tuple[1] then
    push("failed", { })
else
    pop($stack)
    push($stack .. " (r)", s_tuple)
    if not r_tuple then push($register, s_tuple) end
end
"

|:: consume $stack :failed:?|
    :@jet:
"
local r = pop($stack .. " (r)")
if r then push($stack, r) end
"
|:: consume $stack |
    :@jet:
"
pop($stack .. " (r)")
"

|:: push $stack $symbol :failed:?|
|:: push $stack $symbol|
    :@jet:
"
push($stack, { $symbol })
"

|:: pushvar $stack $reg :failed:?|
|:: pushvar $stack $reg|
    :@jet:
"
local r_tuple = pop($reg)
push($stack, r_tuple)
push($reg, r_tuple)
"

|:: unbind $n|
    :@jet:
"
    if stacks[$n].n > 0 then
        pop($n)
    end
"

|:: jet @stdio write/1 :failed:?|
|:: jet @stdio write/1|
    :@jet: "io.write(string.char(tonumber(stacks["1"][1][1])))"

|:stacks:|
    :@stdio.arity: :@stdio.1: :@stdio.2:
    :@stdio.arity (r): :@stdio.1 (r): :@stdio.2 (r):

    :.arity: :.1: :.2:
    :.arity (r): :.1 (r): :.2 (r):
    
    :message.arity: :message.1:
    :message.arity (r): :message.1 (r):

|:registers:|
    :1:

|:: rule 1 succeeded :failed:| :: rule 2
|:: rule 2 succeeded :failed:| :: rule 3
|:: rule 3 succeeded :failed:| :: rule 4
|:: rule $x succeeded :failed:?|
|:: rule $x succeeded| :: rule 1


|:/:| :: print message :message: "Hello, World!"
|:: rule 0|
    :: push .arity 2 :: push .1 print :: push .2 message
    :: push message.arity 1 :: push message.1 33
    :: push message.arity 1 :: push message.1 100
    :: push message.arity 1 :: push message.1 108
    :: push message.arity 1 :: push message.1 114
    :: push message.arity 1 :: push message.1 111
    :: push message.arity 1 :: push message.1 87
    :: push message.arity 1 :: push message.1 32
    :: push message.arity 1 :: push message.1 44
    :: push message.arity 1 :: push message.1 111
    :: push message.arity 1 :: push message.1 108
    :: push message.arity 1 :: push message.1 108
    :: push message.arity 1 :: push message.1 101
    :: push message.arity 1 :: push message.1 72
    :: rule 0 succeeded

|:@stdio: write $char|
    :@jet: "io.write(string.char(tonumber($char)))"
|:: rule 1|
    :: match @stdio.arity 2 :: match @stdio.1 write :: bind @stdio.2 1
    :: consume @stdio.arity
    :: consume @stdio.1
    :: consume @stdio.2
    :: jet @stdio write/1
    :: unbind 1
    :: rule 1 succeeded

|:: print message? :message: $char|
    :@stdio: write $char
|:: rule 2|
    :: match .arity 2 :: match .1 print :: match .2 message
    :: match message.arity 1 :: bind message.1 1
    :: consume .arity :: consume .1 :: consume .2
    :: consume message.arity :: consume message.1
    :: push @stdio.arity 2 :: push @stdio.1 write :: pushvar @stdio.2 1
    :: push .arity 2 :: push .1 print :: push .2 message
    :: unbind 1
    :: rule 2 succeeded


|:: print message|
    :@stdio: write 10
|:: rule 3|
    :: match .arity 2 :: match .1 print :: match .2 message
    :: consume .arity :: consume .1 :: consume .2
    :: push @stdio.arity 2 :: push @stdio.1 write :: push @stdio.2 10
    :: unbind 1
    :: rule 3 succeeded


|| :: rule 0