85 lines
1.5 KiB
QBasic
85 lines
1.5 KiB
QBasic
' This script is an example of MY-BASIC
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' Copyright (c) 2011 - 2016 Wang Renxin. All rights reserved.
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' For more information, see https://github.com/paladin-t/my_basic/
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def reserve(m, n)
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for j = len(m) to n + 2
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push(m, 0)
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next
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enddef
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def forward(cmd, i)
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l = len(cmd)
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while i < l and mid(cmd, i, 1) <> "]"
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i = i + 1
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wend
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if i < l then
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i = i + 1
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endif
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return i
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enddef
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def backward(cmd, i)
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while i > 0 and mid(cmd, i, 1) <> "["
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i = i - 1
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wend
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if i > 0 then
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i = i - 1
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endif
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return i
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enddef
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def brainfuck(cmd)
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m = list()
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i = 0
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cursor = 0
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l = len(cmd)
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while i < l
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c = mid(cmd, i, 1)
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if c = ">" then
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cursor = cursor + 1
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elseif c = "<" then
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cursor = cursor - 1
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elseif c = "+" then
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reserve(m, cursor)
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b = m(cursor)
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m(cursor) = b + 1
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elseif c = "-" then
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reserve(m, cursor)
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b = m(cursor)
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m(cursor) = b - 1
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elseif c = "." then
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reserve(m, cursor)
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print chr(m(cursor))
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elseif c = "," then
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reserve(m, cursor)
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input ch$
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m(cursor) = asc(ch$)
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elseif c = "[" then
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reserve(m, cursor)
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b = m(cursor)
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if b = 0 then
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i = forward(cmd, i)
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endif
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elseif c = "]" then
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reserve(m, cursor)
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b = m(cursor)
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if b <> 0 then
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i = backward(cmd, i)
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endif
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endif
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i = i + 1
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wend
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enddef
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' This is a brainfuck interpreter written with MY-BASIC
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' Try this code (without brackets): "++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>."
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print "BF: "
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input cmd$
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brainfuck(cmd$)
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