81 lines
2.0 KiB
Plaintext
81 lines
2.0 KiB
Plaintext
# new type to help incrementally scan arrays
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container stream:_elem [
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index:num
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data:&:@:_elem
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]
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def new-stream s:&:@:_elem -> result:&:stream:_elem [
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local-scope
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load-inputs
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return-unless s, null
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result <- new {(stream _elem): type}
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*result <- put *result, index:offset, 0
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*result <- put *result, data:offset, s
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]
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def rewind in:&:stream:_elem -> in:&:stream:_elem [
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local-scope
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load-inputs
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return-unless in
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*in <- put *in, index:offset, 0
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]
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def read in:&:stream:_elem -> result:_elem, empty?:bool, in:&:stream:_elem [
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local-scope
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load-inputs
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assert in, [cannot read; stream has no data]
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empty? <- copy false
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idx:num <- get *in, index:offset
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s:&:@:_elem <- get *in, data:offset
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len:num <- length *s
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at-end?:bool <- greater-or-equal idx len
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{
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break-unless at-end?
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empty-result:&:_elem <- new _elem:type
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return *empty-result, true
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}
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result <- index *s, idx
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idx <- add idx, 1
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*in <- put *in, index:offset, idx
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]
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def peek in:&:stream:_elem -> result:_elem, empty?:bool [
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local-scope
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load-inputs
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assert in, [cannot peek; stream has no data]
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empty?:bool <- copy false
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idx:num <- get *in, index:offset
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s:&:@:_elem <- get *in, data:offset
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len:num <- length *s
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at-end?:bool <- greater-or-equal idx len
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{
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break-unless at-end?
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empty-result:&:_elem <- new _elem:type
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return *empty-result, true
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}
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result <- index *s, idx
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]
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def read-line in:&:stream:char -> result:text, in:&:stream:char [
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local-scope
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load-inputs
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assert in, [cannot read-line; stream has no data]
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idx:num <- get *in, index:offset
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s:text <- get *in, data:offset
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next-idx:num <- find-next s, 10/newline, idx
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result <- copy-range s, idx, next-idx
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idx <- add next-idx, 1 # skip newline
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# write back
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*in <- put *in, index:offset, idx
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]
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def end-of-stream? in:&:stream:_elem -> result:bool [
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local-scope
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load-inputs
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assert in, [cannot check end-of-stream?; stream has no data]
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idx:num <- get *in, index:offset
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s:&:@:_elem <- get *in, data:offset
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len:num <- length *s
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result <- greater-or-equal idx, len
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]
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