# Chessboard program: you type in moves in algebraic notation, and it'll # display the position after each move. # recipes are mu's names for functions recipe main [ open-console # take control of screen, keyboard and mouse # The chessboard recipe takes keyboard and screen objects as 'ingredients'. # # In mu it is good form (though not required) to explicitly show the # hardware you rely on. # # The chessboard also returns the same keyboard and screen objects. In mu it # is good form to not modify ingredients of a recipe unless they are also # results. Here we clearly modify both keyboard and screen, so we return # both. # # Here the console and screen are both 0, which usually indicates real # hardware rather than a fake for testing as you'll see below. 0:literal/screen, 0:literal/console <- chessboard 0:literal/screen, 0:literal/console close-console # cleanup screen, keyboard and mouse ] ## But enough about mu. Here's what it looks like to run the chessboard program. scenario print-board-and-read-move [ $close-trace # administrivia: most scenarios save and check traces, but this one gets too large/slow # we'll make the screen really wide because the program currently prints out a long line assume-screen 120:literal/width, 20:literal/height # initialize keyboard to type in a move assume-console [ type [a2-a4 ] ] run [ screen:address, console:address <- chessboard screen:address, console:address #? $browse-trace #? 1 #? $close-trace #? 1 # icon for the cursor screen:address <- print-character screen:address, 9251:literal # '␣' ] screen-should-contain [ # 1 2 3 4 5 6 7 8 9 10 11 # 012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789 .Stupid text-mode chessboard. White pieces in uppercase; black pieces in lowercase. No checking for legal moves. . . . .8 | r n b q k b n r . .7 | p p p p p p p p . .6 | . .5 | . .4 | P . .3 | . .2 | P P P P P P P . .1 | R N B Q K B N R . . +---------------- . . a b c d e f g h . . . .Type in your move as -. For example: 'a2-a4'. Then press . . . . .Hit 'q' to exit. . . . .move: ␣ . . . . . ] ] #? scenario foo [ #? 1 #? $print [aaa] #? 1 #? run [ #? 1 #? 1:number <- copy 34:literal #? 1 #? ] #? 1 #? memory-should-contain [ #? 1 #? 1 <- 34 #? 1 #? ] #? 1 #? $print [zzz] #? 1 #? ] #? 1 ## Here's how 'chessboard' is implemented. recipe chessboard [ #? $start-tracing [schedule] #? 2 #? $start-tracing #? 1 new-default-space screen:address <- next-ingredient console:address <- next-ingredient #? $print [screen: ], screen:address, [, console: ], console:address, [ #? ] #? 1 board:address:array:address:array:character <- initial-position # hook up stdin stdin:address:channel <- new-channel 10:literal/capacity start-running send-keys-to-channel:recipe, console:address, stdin:address:channel, screen:address # buffer lines in stdin buffered-stdin:address:channel <- new-channel 10:literal/capacity start-running buffer-lines:recipe, stdin:address:channel, buffered-stdin:address:channel { msg:address:array:character <- new [Stupid text-mode chessboard. White pieces in uppercase; black pieces in lowercase. No checking for legal moves. ] print-string screen:address, msg:address:array:character #? $print [aaa #? ] #? 1 cursor-to-next-line screen:address print-board screen:address, board:address:array:address:array:character cursor-to-next-line screen:address msg:address:array:character <- new [Type in your move as -. For example: 'a2-a4'. Then press . ] print-string screen:address, msg:address:array:character #? $print [bbb #? ] #? 1 cursor-to-next-line screen:address msg:address:array:character <- new [Hit 'q' to exit. ] print-string screen:address, msg:address:array:character #? $print [ccc #? ] #? 1 { cursor-to-next-line screen:address msg:address:array:character <- new [move: ] print-string screen:address, msg:address:array:character #? $print [ddd #? ] #? 1 m:address:move, quit:boolean, error:boolean <- read-move buffered-stdin:address:channel, screen:address #? $print [eee #? ] #? 1 break-if quit:boolean, +quit:offset buffered-stdin:address:channel <- clear-channel buffered-stdin:address:channel # cleanup after error. todo: test this? loop-if error:boolean } board:address:array:address:array:character <- make-move board:address:array:address:array:character, m:address:move clear-screen screen:address loop } +quit #? $print [aaa] #? 1 ] ## a board is an array of files, a file is an array of characters (squares) recipe new-board [ new-default-space initial-position:address:array:number <- next-ingredient # assert(length(initial-position) == 64) len:number <- length initial-position:address:array:number/deref correct-length?:boolean <- equal len:number, 64:literal assert correct-length?:boolean, [chessboard had incorrect size] # board is an array of pointers to files; file is an array of characters board:address:array:address:array:character <- new location:type, 8:literal col:number <- copy 0:literal { done?:boolean <- equal col:number, 8:literal break-if done?:boolean file:address:address:array:character <- index-address board:address:array:address:array:character/deref, col:number file:address:address:array:character/deref <- new-file initial-position:address:array:number, col:number col:number <- add col:number, 1:literal loop } reply board:address:array:address:array:character ] recipe new-file [ new-default-space position:address:array:number <- next-ingredient index:number <- next-ingredient index:number <- multiply index:number, 8:literal result:address:array:character <- new character:type, 8:literal row:number <- copy 0:literal { done?:boolean <- equal row:number, 8:literal break-if done?:boolean dest:address:character <- index-address result:address:array:character/deref, row:number dest:address:character/deref <- index position:address:array:number/deref, index:number row:number <- add row:number, 1:literal index:number <- add index:number, 1:literal loop } reply result:address:array:character ] recipe print-board [ new-default-space screen:address <- next-ingredient board:address:array:address:array:character <- next-ingredient row:number <- copy 7:literal # start printing from the top of the board # print each row #? $print [printing board to screen ], screen:address, [ #? ] #? 1 { done?:boolean <- lesser-than row:number, 0:literal break-if done?:boolean #? $print [printing rank ], row:number, [ #? ] #? 1 # print rank number as a legend rank:number <- add row:number, 1:literal print-integer screen:address, rank:number s:address:array:character <- new [ | ] print-string screen:address, s:address:array:character # print each square in the row col:number <- copy 0:literal { done?:boolean <- equal col:number, 8:literal break-if done?:boolean f:address:array:character <- index board:address:array:address:array:character/deref, col:number c:character <- index f:address:array:character/deref, row:number print-character screen:address, c:character print-character screen:address, 32:literal # ' ' col:number <- add col:number, 1:literal loop } row:number <- subtract row:number, 1:literal cursor-to-next-line screen:address loop } # print file letters as legend #? $print [printing legend #? ] #? 1 s:address:array:character <- new [ +----------------] print-string screen:address, s:address:array:character screen:address <- cursor-to-next-line screen:address #? screen:address <- print-character screen:address, 97:literal #? 1 s:address:array:character <- new [ a b c d e f g h] screen:address <- print-string screen:address, s:address:array:character screen:address <- cursor-to-next-line screen:address #? $print [done printing board #? ] #? 1 ] # board:address:array:address:array:character <- initial-position recipe initial-position [ new-default-space # layout in memory (in raster order): # R P _ _ _ _ p r # N P _ _ _ _ p n # B P _ _ _ _ p b # Q P _ _ _ _ p q # K P _ _ _ _ p k # B P _ _ _ _ p B # N P _ _ _ _ p n # R P _ _ _ _ p r initial-position:address:array:number <- new-array 82:literal/R, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 114:literal/r, 78:literal/N, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 110:literal/n, 66:literal/B, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 98:literal/b, 81:literal/Q, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 113:literal/q, 75:literal/K, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 107:literal/k, 66:literal/B, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 98:literal/b, 78:literal/N, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 110:literal/n, 82:literal/R, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 114:literal/r #? 82:literal/R, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 114:literal/r, #? 78:literal/N, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 110:literal/n, #? 66:literal/B, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 98:literal/b, #? 81:literal/Q, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 113:literal/q, #? 75:literal/K, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 107:literal/k, #? 66:literal/B, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 98:literal/b, #? 78:literal/N, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 110:literal/n, #? 82:literal/R, 80:literal/P, 32:literal/blank, 32:literal/blank, 32:literal/blank, 32:literal/blank, 112:literal/p, 114:literal/r board:address:array:address:array:character <- new-board initial-position:address:array:number reply board:address:array:address:array:character ] scenario printing-the-board [ assume-screen 30:literal/width, 12:literal/height run [ 1:address:array:address:array:character/board <- initial-position screen:address <- print-board screen:address, 1:address:array:address:array:character/board #? $dump-screen #? 1 ] screen-should-contain [ # 012345678901234567890123456789 .8 | r n b q k b n r . .7 | p p p p p p p p . .6 | . .5 | . .4 | . .3 | . .2 | P P P P P P P P . .1 | R N B Q K B N R . . +---------------- . . a b c d e f g h . . . . . ] ] ## data structure: move container move [ # valid range: 0-7 from-file:number from-rank:number to-file:number to-rank:number ] # result:address:move, quit?:boolean, error?:boolean <- read-move stdin:address:channel, screen:address # prints only error messages to screen recipe read-move [ new-default-space stdin:address:channel <- next-ingredient screen:address <- next-ingredient #? $print screen:address #? 1 from-file:number, quit?:boolean, error?:boolean <- read-file stdin:address:channel, screen:address reply-if quit?:boolean, 0:literal/dummy, quit?:boolean, error?:boolean reply-if error?:boolean, 0:literal/dummy, quit?:boolean, error?:boolean #? close-console #? 1 # construct the move object result:address:move <- new move:type x:address:number <- get-address result:address:move/deref, from-file:offset x:address:number/deref <- copy from-file:number x:address:number <- get-address result:address:move/deref, from-rank:offset x:address:number/deref, quit?:boolean, error?:boolean <- read-rank stdin:address:channel, screen:address reply-if quit?:boolean, 0:literal/dummy, quit?:boolean, error?:boolean reply-if error?:boolean, 0:literal/dummy, quit?:boolean, error?:boolean error?:boolean <- expect-from-channel stdin:address:channel, 45:literal/dash, screen:address reply-if error?:boolean, 0:literal/dummy, 0:literal/quit, error?:boolean x:address:number <- get-address result:address:move/deref, to-file:offset x:address:number/deref, quit?:boolean, error?:boolean <- read-file stdin:address:channel, screen:address reply-if quit?:boolean, 0:literal/dummy, quit?:boolean, error?:boolean reply-if error?:boolean, 0:literal/dummy, quit?:boolean, error?:boolean x:address:number <- get-address result:address:move/deref, to-rank:offset x:address:number/deref, quit?:boolean, error?:boolean <- read-rank stdin:address:channel, screen:address reply-if quit?:boolean, 0:literal/dummy, quit?:boolean, error?:boolean reply-if error?:boolean, 0:literal/dummy, quit?:boolean, error?:boolean #? $exit #? 1 error?:boolean <- expect-from-channel stdin:address:channel, 10:literal/newline, screen:address reply-if error?:boolean, 0:literal/dummy, 0:literal/quit, error?:boolean reply result:address:move, quit?:boolean, error?:boolean ] # file:number, quit:boolean, error:boolean <- read-file stdin:address:channel, screen:address # valid values for file: 0-7 recipe read-file [ new-default-space stdin:address:channel <- next-ingredient screen:address <- next-ingredient c:character, stdin:address:channel <- read stdin:address:channel { q-pressed?:boolean <- equal c:character, 81:literal # 'Q' break-unless q-pressed?:boolean reply 0:literal/dummy, 1:literal/quit, 0:literal/error } { q-pressed?:boolean <- equal c:character, 113:literal # 'q' break-unless q-pressed?:boolean reply 0:literal/dummy, 1:literal/quit, 0:literal/error } { empty-fake-keyboard?:boolean <- equal c:character, 0:literal/eof break-unless empty-fake-keyboard?:boolean reply 0:literal/dummy, 1:literal/quit, 0:literal/error } { newline?:boolean <- equal c:character, 10:literal/newline break-unless newline?:boolean error-message:address:array:character <- new [that's not enough] print-string screen:address, error-message:address:array:character reply 0:literal/dummy, 0:literal/quit, 1:literal/error } file:number <- subtract c:character, 97:literal # 'a' #? $print file:number, [ #? ] #? 1 # 'a' <= file <= 'h' { above-min:boolean <- greater-or-equal file:number, 0:literal break-if above-min:boolean error-message:address:array:character <- new [file too low: ] print-string screen:address, error-message:address:array:character print-character screen:address, c:character cursor-to-next-line screen:address reply 0:literal/dummy, 0:literal/quit, 1:literal/error } { below-max:boolean <- lesser-than file:number, 8:literal break-if below-max:boolean error-message:address:array:character <- new [file too high: ] print-string screen:address, error-message:address:array:character print-character screen:address, c:character reply 0:literal/dummy, 0:literal/quit, 1:literal/error } reply file:number, 0:literal/quit, 0:literal/error ] # rank:number <- read-rank stdin:address:channel, screen:address # valid values: 0-7, -1 (quit), -2 (error) recipe read-rank [ new-default-space stdin:address:channel <- next-ingredient screen:address <- next-ingredient c:character, stdin:address:channel <- read stdin:address:channel { q-pressed?:boolean <- equal c:character, 81:literal # 'Q' break-unless q-pressed?:boolean reply 0:literal/dummy, 1:literal/quit, 0:literal/error } { q-pressed?:boolean <- equal c:character, 113:literal # 'q' break-unless q-pressed?:boolean reply 0:literal/dummy, 1:literal/quit, 0:literal/error } { newline?:boolean <- equal c:character, 10:literal # newline break-unless newline?:boolean error-message:address:array:character <- new [that's not enough] print-string screen:address, error-message:address:array:character reply 0:literal/dummy, 0:literal/quit, 1:literal/error } rank:number <- subtract c:character, 49:literal # '1' #? $print rank:number, [ #? ] #? 1 # assert'1' <= rank <= '8' { above-min:boolean <- greater-or-equal rank:number, 0:literal break-if above-min:boolean error-message:address:array:character <- new [rank too low: ] print-string screen:address, error-message:address:array:character print-character screen:address, c:character reply 0:literal/dummy, 0:literal/quit, 1:literal/error } { below-max:boolean <- lesser-or-equal rank:number, 7:literal break-if below-max:boolean error-message:address:array:character <- new [rank too high: ] print-string screen:address, error-message:address:array:character print-character screen:address, c:character reply 0:literal/dummy, 0:literal/quit, 1:literal/error } reply rank:number, 0:literal/quit, 0:literal/error ] # read a character from the given channel and check that it's what we expect # return true on error recipe expect-from-channel [ new-default-space stdin:address:channel <- next-ingredient expected:character <- next-ingredient screen:address <- next-ingredient c:character, stdin:address:channel <- read stdin:address:channel match?:boolean <- equal c:character, expected:character { break-if match?:boolean s:address:array:character <- new [expected character not found] print-string screen:address, s:address:array:character } result:boolean <- not match?:boolean reply result:boolean ] scenario read-move-blocking [ assume-screen 20:literal/width, 2:literal/height run [ #? $start-tracing #? 1 1:address:channel <- new-channel 2:literal #? $print [aaa channel address: ], 1:address:channel, [ #? ] #? 1 2:number/routine <- start-running read-move:recipe, 1:address:channel, screen:address # 'read-move' is waiting for input wait-for-routine 2:number #? $print [bbb channel address: ], 1:address:channel, [ #? ] #? 1 3:number <- routine-state 2:number/id #? $print [I: routine ], 2:number, [ state ], 3:number [ #? ] #? 1 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?, [ F read-move-blocking: routine failed to pause after coming up (before any keys were pressed)] # press 'a' #? $print [ccc channel address: ], 1:address:channel, [ #? ] #? 1 #? $exit #? 1 1:address:channel <- write 1:address:channel, 97:literal # 'a' restart 2:number/routine # 'read-move' still waiting for input wait-for-routine 2:number 3:number <- routine-state 2:number/id #? $print [II: routine ], 2:number, [ state ], 3:number [ #? ] #? 1 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?, [ F read-move-blocking: routine failed to pause after rank 'a'] # press '2' 1:address:channel <- write 1:address:channel, 50:literal # '2' restart 2:number/routine # 'read-move' still waiting for input wait-for-routine 2:number 3:number <- routine-state 2:number/id #? $print [III: routine ], 2:number, [ state ], 3:number [ #? ] #? 1 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?, [ F read-move-blocking: routine failed to pause after file 'a2'] # press '-' 1:address:channel <- write 1:address:channel, 45:literal # '-' restart 2:number/routine # 'read-move' still waiting for input wait-for-routine 2:number 3:number <- routine-state 2:number #? $print [IV: routine ], 2:number, [ state ], 3:number [ #? ] #? 1 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?/routine-state, [ F read-move-blocking: routine failed to pause after hyphen 'a2-'] # press 'a' 1:address:channel <- write 1:address:channel, 97:literal # 'a' restart 2:number/routine # 'read-move' still waiting for input wait-for-routine 2:number 3:number <- routine-state 2:number #? $print [V: routine ], 2:number, [ state ], 3:number [ #? ] #? 1 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?/routine-state, [ F read-move-blocking: routine failed to pause after rank 'a2-a'] # press '4' 1:address:channel <- write 1:address:channel, 52:literal # '4' restart 2:number/routine # 'read-move' still waiting for input wait-for-routine 2:number 3:number <- routine-state 2:number #? $print [VI: routine ], 2:number, [ state ], 3:number [ #? ] #? 1 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?, [ F read-move-blocking: routine failed to pause after file 'a2-a4'] # press 'newline' 1:address:channel <- write 1:address:channel, 10:literal # newline restart 2:number/routine # 'read-move' now completes wait-for-routine 2:number 3:number <- routine-state 2:number #? $print [VII: routine ], 2:number, [ state ], 3:number [ #? ] #? 1 4:boolean/completed? <- equal 3:number/routine-state, 1:literal/completed assert 4:boolean/completed?, [ F read-move-blocking: routine failed to terminate on newline] trace [test], [reached end] ] trace-should-contain [ test: reached end ] ] scenario read-move-quit [ assume-screen 20:literal/width, 2:literal/height run [ 1:address:channel <- new-channel 2:literal 2:number/routine <- start-running read-move:recipe, 1:address:channel, screen:address # 'read-move' is waiting for input wait-for-routine 2:number 3:number <- routine-state 2:number/id 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?, [ F read-move-quit: routine failed to pause after coming up (before any keys were pressed)] # press 'q' 1:address:channel <- write 1:address:channel, 113:literal # 'q' restart 2:number/routine # 'read-move' completes wait-for-routine 2:number 3:number <- routine-state 2:number/id 4:boolean/completed? <- equal 3:number/routine-state, 1:literal/completed assert 4:boolean/completed?, [ F read-move-quit: routine failed to terminate on 'q'] trace [test], [reached end] ] trace-should-contain [ test: reached end ] ] scenario read-move-illegal-file [ assume-screen 20:literal/width, 2:literal/height run [ 1:address:channel <- new-channel 2:literal 2:number/routine <- start-running read-move:recipe, 1:address:channel, screen:address # 'read-move' is waiting for input wait-for-routine 2:number 3:number <- routine-state 2:number/id 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?, [ F read-move-file: routine failed to pause after coming up (before any keys were pressed)] 1:address:channel <- write 1:address:channel, 50:literal # '2' restart 2:number/routine wait-for-routine 2:number ] screen-should-contain [ .file too low: 2 . . . ] ] scenario read-move-illegal-rank [ assume-screen 20:literal/width, 2:literal/height run [ 1:address:channel <- new-channel 2:literal 2:number/routine <- start-running read-move:recipe, 1:address:channel, screen:address # 'read-move' is waiting for input wait-for-routine 2:number 3:number <- routine-state 2:number/id 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?, [ F read-move-file: routine failed to pause after coming up (before any keys were pressed)] 1:address:channel <- write 1:address:channel, 97:literal # 'a' 1:address:channel <- write 1:address:channel, 97:literal # 'a' restart 2:number/routine wait-for-routine 2:number ] screen-should-contain [ .rank too high: a . . . ] ] scenario read-move-empty [ assume-screen 20:literal/width, 2:literal/height run [ 1:address:channel <- new-channel 2:literal 2:number/routine <- start-running read-move:recipe, 1:address:channel, screen:address # 'read-move' is waiting for input wait-for-routine 2:number 3:number <- routine-state 2:number/id 4:boolean/waiting? <- equal 3:number/routine-state, 2:literal/waiting assert 4:boolean/waiting?, [ F read-move-file: routine failed to pause after coming up (before any keys were pressed)] 1:address:channel <- write 1:address:channel, 10:literal/newline 1:address:channel <- write 1:address:channel, 97:literal # 'a' restart 2:number/routine wait-for-routine 2:number ] screen-should-contain [ .that's not enough . . . ] ] recipe make-move [ new-default-space b:address:array:address:array:character <- next-ingredient m:address:move <- next-ingredient from-file:number <- get m:address:move/deref, from-file:offset #? $print from-file:number, [ #? ] #? 1 from-rank:number <- get m:address:move/deref, from-rank:offset #? $print from-rank:number, [ #? ] #? 1 to-file:number <- get m:address:move/deref, to-file:offset #? $print to-file:number, [ #? ] #? 1 to-rank:number <- get m:address:move/deref, to-rank:offset #? $print to-rank:number, [ #? ] #? 1 f:address:array:character <- index b:address:array:address:array:character/deref, from-file:number src:address:character/square <- index-address f:address:array:character/deref, from-rank:number f:address:array:character <- index b:address:array:address:array:character/deref, to-file:number dest:address:character/square <- index-address f:address:array:character/deref, to-rank:number #? $print src:address:character/deref, [ #? ] #? 1 dest:address:character/deref/square <- copy src:address:character/deref/square src:address:character/deref/square <- copy 32:literal # ' ' reply b:address:array:address:array:character/same-as-ingredient:0 ] scenario making-a-move [ assume-screen 30:literal/width, 12:literal/height run [ 2:address:array:address:array:character/board <- initial-position 3:address:move <- new move:type 4:address:number <- get-address 3:address:move/deref, from-file:offset 4:address:number/deref <- copy 6:literal/g 5:address:number <- get-address 3:address:move/deref, from-rank:offset 5:address:number/deref <- copy 1:literal/2 6:address:number <- get-address 3:address:move/deref, to-file:offset 6:address:number/deref <- copy 6:literal/g 7:address:number <- get-address 3:address:move/deref, to-rank:offset 7:address:number/deref <- copy 3:literal/4 2:address:array:address:array:character/board <- make-move 2:address:array:address:array:character/board, 3:address:move screen:address <- print-board screen:address, 2:address:array:address:array:character/board ] screen-should-contain [ # 012345678901234567890123456789 .8 | r n b q k b n r . .7 | p p p p p p p p . .6 | . .5 | . .4 | P . .3 | . .2 | P P P P P P P . .1 | R N B Q K B N R . . +---------------- . . a b c d e f g h . . . ] ]