Lawrence Bethlenfalvy
ba0b155ebd
Converted the function integration to use template metaprogramming instead of macros.
74 lines
1.5 KiB
Plaintext
74 lines
1.5 KiB
Plaintext
import super::(bool::*, fn::*, known::*, list, option, loop::*, proc::*)
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import std::panic
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-- utilities for using lists as pairs
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export const fst := \l. (
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list::get l 0
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(panic "nonempty expected")
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\x.x
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)
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export const snd := \l. (
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list::get l 1
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(panic "2 elements expected")
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\x.x
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)
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-- constructors
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export const empty := list::end
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export const add := \m.\k.\v. (
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list::cons
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list::new[k, v]
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m
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)
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-- queries
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-- return the last occurrence of a key if exists
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export const get := \m.\key. (
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loop_over (m) {
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cps record, m = list::pop m option::none;
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cps if fst record == key
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then return $ option::some $ snd record
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else identity;
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}
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)
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-- commands
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-- remove one occurrence of a key
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export const del := \m.\k. (
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recursive r (m)
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list::pop m list::end \head.\tail.
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if fst head == k then tail
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else list::cons head $ r tail
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)
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-- remove all occurrences of a key
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export const delall := \m.\k. (
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list::filter m \record. fst record != k
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)
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-- replace at most one occurrence of a key
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export const set := \m.\k.\v. (
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m
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|> del k
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|> add k v
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)
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-- ensure that there's only one instance of each key in the map
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export const normalize := \m. (
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recursive r (m, normal=empty)
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list::pop m normal \head.\tail.
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r tail $ set normal (fst head) (snd head)
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)
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macro new[...$tail:2, ...$key = ...$value:1] =0x2p84=> (
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set new[...$tail] (...$key) (...$value)
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)
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macro new[...$key = ...$value:1] =0x1p84=> (add empty (...$key) (...$value))
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macro new[] =0x1p84=> empty
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export ::(new)
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