# Chessboard program: you type in moves in algebraic notation, and it'll
# display the position after each move.
def main [
local-scope
open-console # take control of screen, keyboard and mouse
clear-screen null/screen # non-scrolling app
# The chessboard function takes keyboard and screen objects as inputs.
#
# In Mu it is good form (though not required) to explicitly state what
# hardware a function needs.
#
# Here the console and screen are both null, which usually indicates real
# hardware rather than a fake for testing as you'll see below.
chessboard null/screen, null/console
close-console # clean up 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 [
local-scope
trace-until 100/app
# we'll make the screen really wide because the program currently prints out a long line
assume-screen 120/width, 20/height
# initialize keyboard to type in a move
assume-console [
type [a2-a4
]
]
run [
screen, console <- chessboard screen, console
# icon for the cursor
cursor-icon:char <- copy 9251/␣
screen <- print screen, cursor-icon
]
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 <from square>-<to square>. For example: 'a2-a4'. Then press <enter>. .
. .
.Hit 'q' to exit. .
. .
.move: ␣ .
. .
. .
]
]
## Here's how 'chessboard' is implemented.
type board = &:@:&:@:char # a 2-D array of arrays of characters
def chessboard screen:&:screen, console:&:console -> screen:&:screen, console:&:console [
local-scope
load-inputs
board:board <- initial-position
# hook up stdin
stdin-in:&:source:char, stdin-out:&:sink:char <- new-channel 10/capacity
start-running send-keys-to-channel, console, stdin-out, screen
# buffer lines in stdin
buffered-stdin-in:&:source:char, buffered-stdin-out:&:sink:char <- new-channel 10/capacity
start-running buffer-lines, stdin-in, buffered-stdin-out
{
print screen, [Stupid text-mode chessboard. White pieces in uppercase; black pieces in lowercase. No checking for legal moves.
]
cursor-to-next-line screen
print screen, board
cursor-to-next-line screen
print screen, [Type in your move as <from square>-<to square>. For example: 'a2-a4'. Then press <enter>.
]
cursor-to-next-line screen
print screen [Hit 'q' to exit.
]
{
cursor-to-next-line screen
screen <- print screen, [move: ]
m:&:move, quit:bool, error:bool <- read-move buffered-stdin-in, screen
break-if quit, +quit
buffered-stdin-in <- clear buffered-stdin-in # cleanup after error. todo: test this?
loop-if error
}
board <- make-move board, m
screen <- clear-screen screen
loop
}
+quit
]
## a board is an array of files, a file is an array of characters (squares)
def new-board initial-position:&:@:char -> board:board [
local-scope
load-inputs
# assert(length(initial-position) == 64)
len:num <- length *initial-position
correct-length?:bool <- equal len, 64
assert correct-length?, [chessboard had incorrect size]
# board is an array of pointers to files; file is an array of characters
board <- new {(address array character): type}, 8
col:num <- copy 0
{
done?:bool <- equal col, 8
break-if done?
file:&:@:char <- new-file initial-position, col
*board <- put-index *board, col, file
col <- add col, 1
loop
}
]
def new-file position:&:@:char, index:num -> result:&:@:char [
local-scope
load-inputs
index <- multiply index, 8
result <- new character:type, 8
row:num <- copy 0
{
done?:bool <- equal row, 8
break-if done?
square:char <- index *position, index
*result <- put-index *result, row, square
row <- add row, 1
index <- add index, 1
loop
}
]
def print screen:&:screen, board:board -> screen:&:screen [
local-scope
load-inputs
row:num <- copy 7 # start printing from the top of the board
space:char <- copy 32/space
# print each row
{
done?:bool <- lesser-than row, 0
break-if done?
# print rank number as a legend
rank:num <- add row, 1
print screen, rank
print screen, [ | ]
# print each square in the row
col:num <- copy 0
{
done?:bool <- equal col:num, 8
break-if done?
f:&:@:char <- index *board, col
c:char <- index *f, row
bg:num <- square-color row, col
print screen, c, 7/white, bg
print screen, space
col <- add col, 1
loop
}
row <- subtract row, 1
cursor-to-next-line screen
loop
}
# print file letters as legend
print screen, [ +----------------]
cursor-to-next-line screen
print screen, [ a b c d e f g h]
cursor-to-next-line screen
]
def square-color row:num, col:num -> result:num [
local-scope
load-inputs
result <- copy 0/black
x:num <- add row, col
_, rem:num <- divide-with-remainder x, 2
return-if rem, 238
]
def initial-position -> board:board [
local-scope
# 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:&:@:char <- new-array 82/R, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 114/r, 78/N, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 110/n, 66/B, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 98/b, 81/Q, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 113/q, 75/K, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 107/k, 66/B, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 98/b, 78/N, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 110/n, 82/R, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 114/r
#? 82/R, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 114/r,
#? 78/N, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 110/n,
#? 66/B, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 98/b,
#? 81/Q, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 113/q,
#? 75/K, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 107/k,
#? 66/B, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 98/b,
#? 78/N, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 110/n,
#? 82/R, 80/P, 32/blank, 32/blank, 32/blank, 32/blank, 112/p, 114/r
board <- new-board initial-position
]
scenario printing-the-board [
local-scope
board:board <- initial-position
assume-screen 30/width, 12/height
run [
screen <- print screen, 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 | .
.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:num
from-rank:num
to-file:num
to-rank:num
]
# prints only error messages to screen
def read-move stdin:&:source:char, screen:&:screen -> result:&:move, quit?:bool, error?:bool, stdin:&:source:char, screen:&:screen [
local-scope
load-inputs
from-file:num, quit?:bool, error?:bool <- read-file stdin, screen
return-if quit?, null/dummy
return-if error?, null/dummy
# construct the move object
result:&:move <- new move:type
*result <- put *result, from-file:offset, from-file
from-rank:num, quit?, error? <- read-rank stdin, screen
return-if quit?, null/dummy
return-if error?, null/dummy
*result <- put *result, from-rank:offset, from-rank
error? <- expect-from-channel stdin, 45/dash, screen
return-if error?, null/dummy, false/quit
to-file:num, quit?, error? <- read-file stdin, screen
return-if quit?, null/dummy
return-if error?, null/dummy
*result <- put *result, to-file:offset, to-file
to-rank:num, quit?, error? <- read-rank stdin, screen
return-if quit?, null/dummy
return-if error?, null/dummy
*result <- put *result, to-rank:offset, to-rank
error? <- expect-from-channel stdin, 10/newline, screen
return-if error?, null/dummy, false/quit
]
# valid values for file: 0-7
def read-file stdin:&:source:char, screen:&:screen -> file:num, quit:bool, error:bool, stdin:&:source:char, screen:&:screen [
local-scope
load-inputs
c:char, eof?:bool, stdin <- read stdin
return-if eof?, 0/dummy, true/quit, false/no-error
q-pressed?:bool <- equal c, 81/Q
return-if q-pressed?, 0/dummy, true/quit, false/no-error
q-pressed? <- equal c, 113/q
return-if q-pressed?, 0/dummy, true/quit, false/no-error
empty-fake-keyboard?:bool <- equal c, 0/eof
return-if empty-fake-keyboard?, 0/dummy, true/quit, false/no-error
{
newline?:bool <- equal c, 10/newline
break-unless newline?
print screen, [that's not enough]
return 0/dummy, false/don't-quit, true/error
}
file:num <- subtract c, 97/a
# 'a' <= file <= 'h'
{
above-min:bool <- greater-or-equal file, 0
break-if above-min
print screen, [file too low: ]
print screen, c
cursor-to-next-line screen
return 0/dummy, false/don't-quit, true/error
}
{
below-max:bool <- lesser-than file, 8
break-if below-max
print screen, [file too high: ]
print screen, c
return 0/dummy, false/don't-quit, true/error
}
return file, false/don't-quit, false/no-error
]
# valid values for rank: 0-7
def read-rank stdin:&:source:char, screen:&:screen -> rank:num, quit?:bool, error?:bool, stdin:&:source:char, screen:&:screen [
local-scope
load-inputs
c:char, eof?:bool, stdin <- read stdin
return-if eof?, 0/dummy, true/quit, false/no-error
q-pressed?:bool <- equal c, 81/Q
return-if q-pressed?, 0/dummy, true/quit, false/no-error
q-pressed? <- equal c, 113/q
return-if q-pressed?, 0/dummy, true/quit, false/no-error
empty-fake-keyboard?:bool <- equal c, 0/eof
return-if empty-fake-keyboard?, 0/dummy, true/quit, false/no-error
{
newline?:bool <- equal c, 10 # newline
break-unless newline?
print screen, [that's not enough]
return 0/dummy, false/don't-quite, true/error
}
rank:num <- subtract c, 49/'1'
# assert'1' <= rank <= '8'
{
above-min:bool <- greater-or-equal rank, 0
break-if above-min
print screen, [rank too low: ]
print screen, c
return 0/dummy, false/don't-quite, true/error
}
{
below-max:bool <- lesser-or-equal rank, 7
break-if below-max
print screen, [rank too high: ]
print screen, c
return 0/dummy, false/don't-quite, true/error
}
return rank, false/don't-quite, false/no-error
]
# read a character from the given channel and check that it's what we expect
# return true on error
def expect-from-channel stdin:&:source:char, expected:char, screen:&:screen -> result:bool, stdin:&:source:char, screen:&:screen [
local-scope
load-inputs
c:char, eof?:bool, stdin <- read stdin
return-if eof? true
{
match?:bool <- equal c, expected
break-if match?
print screen, [expected character not found]
}
result <- not match?
]
scenario read-move-blocking [
local-scope
assume-screen 20/width, 2/height
source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
read-move-routine:num/routine <- start-running read-move, source, screen
run [
# 'read-move' is waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state:num <- routine-state read-move-routine
waiting?:bool <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-blocking: routine failed to pause after coming up (before any keys were pressed)]
# press 'a'
sink <- write sink, 97/a
restart read-move-routine
# 'read-move' still waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state <- routine-state read-move-routine
waiting? <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-blocking: routine failed to pause after rank 'a']
# press '2'
sink <- write sink, 50/'2'
restart read-move-routine
# 'read-move' still waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state <- routine-state read-move-routine
waiting? <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-blocking: routine failed to pause after file 'a2']
# press '-'
sink <- write sink, 45/'-'
restart read-move-routine
# 'read-move' still waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state <- routine-state read-move-routine
waiting? <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-blocking: routine failed to pause after hyphen 'a2-']
# press 'a'
sink <- write sink, 97/a
restart read-move-routine
# 'read-move' still waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state <- routine-state read-move-routine
waiting? <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-blocking: routine failed to pause after rank 'a2-a']
# press '4'
sink <- write sink, 52/'4'
restart read-move-routine
# 'read-move' still waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state <- routine-state read-move-routine
waiting? <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-blocking: routine failed to pause after file 'a2-a4']
# press 'newline'
sink <- write sink, 10 # newline
restart read-move-routine
# 'read-move' now completes
wait-for-routine-to-block read-move-routine
read-move-state <- routine-state read-move-routine
completed?:bool <- equal read-move-state, 1/completed
assert completed?, [
F read-move-blocking: routine failed to terminate on newline]
trace 1, [test], [reached end]
]
trace-should-contain [
test: reached end
]
]
scenario read-move-quit [
local-scope
assume-screen 20/width, 2/height
source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
read-move-routine:num <- start-running read-move, source, screen
run [
# 'read-move' is waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state:num <- routine-state read-move-routine
waiting?:bool <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-quit: routine failed to pause after coming up (before any keys were pressed)]
# press 'q'
sink <- write sink, 113/q
restart read-move-routine
# 'read-move' completes
wait-for-routine-to-block read-move-routine
read-move-state <- routine-state read-move-routine
completed?:bool <- equal read-move-state, 1/completed
assert completed?, [
F read-move-quit: routine failed to terminate on 'q']
trace 1, [test], [reached end]
]
trace-should-contain [
test: reached end
]
]
scenario read-move-illegal-file [
local-scope
assume-screen 20/width, 2/height
source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
read-move-routine:num <- start-running read-move, source, screen
run [
# 'read-move' is waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state:num <- routine-state read-move-routine
waiting?:bool <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-illegal-file: routine failed to pause after coming up (before any keys were pressed)]
sink <- write sink, 50/'2'
restart read-move-routine
wait-for-routine-to-block read-move-routine
]
screen-should-contain [
.file too low: 2 .
. .
]
]
scenario read-move-illegal-rank [
local-scope
assume-screen 20/width, 2/height
source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
read-move-routine:num <- start-running read-move, source, screen
run [
# 'read-move' is waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state:num <- routine-state read-move-routine
waiting?:bool <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-illegal-rank: routine failed to pause after coming up (before any keys were pressed)]
sink <- write sink, 97/a
sink <- write sink, 97/a
restart read-move-routine
wait-for-routine-to-block read-move-routine
]
screen-should-contain [
.rank too high: a .
. .
]
]
scenario read-move-empty [
local-scope
assume-screen 20/width, 2/height
source:&:source:char, sink:&:sink:char <- new-channel 2/capacity
read-move-routine:num <- start-running read-move, source, screen
run [
# 'read-move' is waiting for keypress
wait-for-routine-to-block read-move-routine
read-move-state:num <- routine-state read-move-routine
waiting?:bool <- not-equal read-move-state, 2/discontinued
assert waiting?, [
F read-move-empty: routine failed to pause after coming up (before any keys were pressed)]
sink <- write sink, 10/newline
sink <- write sink, 97/a
restart read-move-routine
wait-for-routine-to-block read-move-routine
]
screen-should-contain [
.that's not enough .
. .
]
]
def make-move board:board, m:&:move -> board:board [
local-scope
load-inputs
from-file:num <- get *m, from-file:offset
from-rank:num <- get *m, from-rank:offset
to-file:num <- get *m, to-file:offset
to-rank:num <- get *m, to-rank:offset
from-f:&:@:char <- index *board, from-file
to-f:&:@:char <- index *board, to-file
src:char/square <- index *from-f, from-rank
*to-f <- put-index *to-f, to-rank, src
*from-f <- put-index *from-f, from-rank, 32/space
]
scenario making-a-move [
local-scope
assume-screen 30/width, 12/height
board:board <- initial-position
move:&:move <- new move:type
*move <- merge 6/g, 1/'2', 6/g, 3/'4'
run [
board <- make-move board, move
screen <- print screen, 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 .
. .
]
]