Execute SNUSP/Tcl
This is an interpreter for Modular SNUSP. Appears to work with correct SNUSP programs... <lang tcl>package require Tcl 8.5
- Basic I/O to read the program data and get ready for execution
set f [open [lindex $argv 0]] set data [read $f] close $f fconfigure stdout -buffering none
- How to access the program
set pc {0 0} set lineNum 0 foreach line [split $data \n] {
set idx [string first \$ $line]
if {$idx >= 0} {
set pc [list $lineNum $idx]
} lappend program [split $line ""] incr lineNum
} set move {0 1} proc Move {} {
global pc move
lset pc 0 [expr {[lindex $pc 0] + [lindex $move 0]}]
lset pc 1 [expr {[lindex $pc 1] + [lindex $move 1]}]
} proc Char {} {
global program pc
set c [lindex $program $pc]
if {$c eq ""} {
return -code break
} return $c
}
- An unbounded datastore
set data 0 set dptr 0 proc Get {} {
global data dptr
if {$dptr < 0} {
puts stderr "program error; data pointer too low"
return -code break
}
while {$dptr >= [llength $data]} {
lappend data 0
} lindex $data $dptr
} proc Set val {
global data dptr
if {$dptr < 0} {
puts stderr "program error; data pointer too low"
return -code break
}
while {$dptr >= [llength $data]} {
lappend data 0
} lset data $dptr $val
}
- An unbounded stack
set stack {} proc Push {} {
global stack pc move set save $pc Move lappend stack [list $pc $move] set pc $save
} proc Pop {} {
global stack pc move
if {[llength $stack] == 0} {
return -code break
} lassign [lindex $stack end] pc move set stack [lrange $stack 0 end-1]
}
- The main interpreter loop; $last is used for tracking whether
- to terminate output with a newline
set last 10 while 1 {
switch -- [Char] {
"/" {set move "[expr -[lindex $move 1]] [expr -[lindex $move 0]]"} "\\" {set move [lreverse $move]} "?" {if ![Get] Move} "!" {Move} ">" {incr dptr} "<" {incr dptr -1} "+" {Set [expr [Get]+1]} "-" {Set [expr [Get]-1]} "." {puts -nonewline [format %c [set last [Get]]]} "," {Set [read stdin 1]} "@" {Push} "#" {Pop}
} Move
} if {$last != 10} {puts ""}</lang>