57 lines
870 B
CoffeeScript
57 lines
870 B
CoffeeScript
# 'sum' function
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#define A p3
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#define B p4
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#define I p5
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#define X p6
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# leaves the sum at the top of the stack
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Eval_sum = ->
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i = 0
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j = 0
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k = 0
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# 1st arg
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body = cadr(p1)
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# 2nd arg (index)
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indexVariable = caddr(p1)
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if (!issymbol(indexVariable))
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stop("sum: 2nd arg?")
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# 3rd arg (lower limit)
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push(cadddr(p1))
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Eval()
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j = pop_integer()
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if (isNaN(j))
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push p1
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return
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# 4th arg (upper limit)
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push(caddddr(p1))
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Eval()
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k = pop_integer()
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if (isNaN(k))
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push p1
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return
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# remember contents of the index
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# variable so we can put it back after the loop
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p4 = get_binding(indexVariable)
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push_integer(0)
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for i in [j..k]
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push_integer(i)
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p5 = pop()
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set_binding(indexVariable, p5)
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push(body)
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Eval()
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add()
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# put back the index variable to original content
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set_binding(indexVariable, p4)
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