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algebrite

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Computer Algebra System in Coffeescript

github.com/davidedc/Algebrite

davidedc/Algebrite

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# _______ # | | <- stack # | | # |_______| # | | <- stack + tos # | | # | | # |_______| # | | <- frame # |_______| # <- stack + TOS # # The stack grows from low memory towards high memory. This is so that # multiple expressions can be pushed on the stack and then accessed as an # array. # # The frame area holds local variables and grows from high memory towards # low memory. The frame area makes local variables visible to the garbage # collector. tos = 0 # p is a U nil_symbols = 0 push = (p) -> if !p? debugger if p.isZero? debugger #console.log "pushing " #print1(p) if p == symbol(NIL) nil_symbols++ if DEBUG then console.log "pushing symbol(NIL) #" + nil_symbols #if nil_symbols == 111 # debugger if (tos >= frame) stop("stack overflow") stack[tos++] = p # returns a U #popsNum = 0 pop = -> #popsNum++ #console.log "pop #" + popsNum if (tos == 0) debugger stop("stack underflow") if !stack[tos-1]? debugger elementToBeReturned = stack[--tos] return elementToBeReturned # n is an integer push_frame = (n) -> i = 0 frame -= n if (frame < tos) debugger stop("frame overflow, circular reference?") for i in [0...n] stack[frame + i] = symbol(NIL) # n is an integer pop_frame = (n) -> frame += n if (frame > TOS) stop("frame underflow") save = -> frame -= 10 if (frame < tos) debugger stop("frame overflow, circular reference?") stack[frame + 0] = p0 stack[frame + 1] = p1 stack[frame + 2] = p2 stack[frame + 3] = p3 stack[frame + 4] = p4 stack[frame + 5] = p5 stack[frame + 6] = p6 stack[frame + 7] = p7 stack[frame + 8] = p8 stack[frame + 9] = p9 restore = -> if (frame > TOS - 10) stop("frame underflow") p0 = stack[frame + 0] p1 = stack[frame + 1] p2 = stack[frame + 2] p3 = stack[frame + 3] p4 = stack[frame + 4] p5 = stack[frame + 5] p6 = stack[frame + 6] p7 = stack[frame + 7] p8 = stack[frame + 8] p9 = stack[frame + 9] frame += 10 # Local U * is OK here because there is no functional path to the garbage collector. swap = -> #U *p, *q # p and q are both Us p = pop() q = pop() push(p) push(q) # Local U * is OK here because there is no functional path to the garbage collector. dupl = -> #U *p p = pop() push(p) push(p)