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Add flat_map(Eachable1, Fun)
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Also move Result up for correctness of get(MatchSuccess)
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@ilyash-b
ilyash-b committed May 25, 2024
1 parent c3bea4b commit 98285e7
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1 change: 1 addition & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
* Add `when(val, pattern, new_val)`
* Add `code(ArrLike)`
* Add `code(Type)`
* Add `flat_map(Eachable1, Fun)`

### Fixes and improvements
* Fix `AtPath` for non-eachables
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246 changes: 132 additions & 114 deletions lib/stdlib.ngs
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Expand Up @@ -817,7 +817,7 @@ section "Hash" {

}

section "Result and friends - types" {
section "Result and friends" {
doc Result of a computation
doc val - computed value or exception
type Result
Expand All @@ -830,6 +830,109 @@ section "Result and friends - types" {
doc val - exception
type Failure(Result)

doc Thrown by get(Failure) as it has no value to get
type ResultFail(Error)

doc Runs the computation and wraps the result: a value is wrapped in Success and an exception is wrapped in Failure.
doc %RET - Success or Failure
F Result(fun:Fun) {
try {
Success(fun())
} catch(e) {
Failure(e)
}
}

doc Initialize Success with the given value.
F init(s:Success, v=null) s.val = v

doc Initialize Failure with the given value.
F init(f:Failure, e:Exception) f.val = e

doc Gets wrapped value
doc %RET - Any
doc %EX - { 1 / 10 }.Result().get() # 0
F get(s:Success) s.val

doc Throws ResultFail
doc %EX - { 1 / 0 }.Result().get() # ResultFail exception
F get(f:Failure) {
throw ResultFail("Can not get value of Failure", f.val)
}

doc Gets wrapped value
doc %RET - Any
doc %EX - { 1 / 10 }.Result().get(100) # 0
F get(s:Success, dflt) s.val

doc Returns dflt
doc %EX - { 1 / 0 }.Result().get(100) # 100
F get(f:Failure, dflt) dflt.Value()

doc %RET - s
F dflt(s:Success, x) s

doc %RET - Value(x,f)
F dflt(f:Failure, x) Success(x.Value(f))

TEST Success(1).dflt(2).get() == 1
TEST Failure(Error("test")).dflt(2).get() == 2

doc Run fun with wrapped value.
F each(s:Success, fun:Fun) {
fun(s.get())
s
}

doc Run fun with wrapped value. If exception is thrown, Failure is returned; otherwise Success with new value is returned.
doc %RET - Result
F map(s:Success, fun:Fun) Result({ fun(s.get()) })

doc No-op, returns f
doc %RET - f
F each(f:Failure, fun:Fun) f

doc No-op, returns f
doc %RET - f
F map(f:Failure, fun:Fun) f

doc Check whether wrapped value matches the pattern.
doc %RET - s or Failure
doc %EX - Success(10).filter(X>5) # <Success val=10>
doc %EX - Success(10).filter(X>15) # <Failure val=<ResultFail ...>>
F filter(s:Success, pattern=Bool.constructors) {
s.val =~ pattern returns s
Failure(ResultFail("Success filtered out, resulting Failure").set('pattern', pattern))
}

TEST Result({100}).filter() == Success(100)

doc No-op, returns f
doc %RET - f
doc %EX - Failure("blah").filter(X>5) # <Failure val=blah>
F filter(f:Failure, pattern=Bool.constructors) f

TEST Result({1/0}).filter() is Failure

doc Convert Success to Bool (true)
doc %RET - true
F Bool(s:Success) true

doc Convert Failure to Bool (false)
doc %RET - false
F Bool(f:Failure) false

doc EXPERIMENTAL! Do not use!
F ExitCode(r:Result) r.Bool().ExitCode()

TEST {read("/etc/passwd")}.Result() is Success
TEST {read("NO-SUCH-FILE")}.Result() is Failure
TEST Success(10).map(X*2).get() == 20
TEST { { throw Error("xx") }.Result().map(X*2).get() }.assert(ResultFail)

doc Convert Success into JSON compatible data structure - the value of the computation
F JsonData(s:Success) s.get().JsonData()

}

section "Literal" {
Expand Down Expand Up @@ -1197,6 +1300,21 @@ F map(e:Eachable, mapper:Fun)
collector
e.each(collect + mapper)

doc Map and flatten.
doc Applies mapper to each element of e, collects results, and flattens the results (one level).
doc %EX - [2,0,4].flat_map(F(e) Result({ 12 / e}).Box()) # [6, 3]
doc %EX - [2,0,4].flat_map(F(e) [1, e*2]) # [1,4, 1,0, 1,8]
F flat_map(e:Eachable1, mapper:Fun) {
collector {
e.each(F(elt) {
elt.mapper().each(collect)
})
}
}

TEST [2,0,4].flat_map(F(e) Result({ 12 / e}).Box()) == [6, 3]
TEST [2,0,4].flat_map(F(e) [1, e*2]) == [1,4, 1,0, 1,8]

doc EXPERIMENTAL! Do not use!
doc Map e to same type. Mnemonics: "map original" / "MAP to Original type".
doc e - object of any type that has each(e, callback) implemented
Expand Down Expand Up @@ -4109,126 +4227,24 @@ section "Box" {
F JsonData(fb:FullBox) fb.get().JsonData()
}

# === Result =====================================

doc Thrown by get(Failure) as it has no value to get
type ResultFail(Error)
section "Results" {

doc Results, an array-like of Result elements
type Results(ArrLike)

F Str(r:Results) "<${r.Type().name} ${r.group(F(x) x.Type().name).mapv(len).map("$X:$Y").join(" ")}>"

doc Results, an array-like of Result elements
type Results(ArrLike)
type ResultsException(Error)
doc ResultsException where only failures are stored
type FailuresException(ResultsException)

F Str(r:Results) "<${r.Type().name} ${r.group(F(x) x.Type().name).mapv(len).map("$X:$Y").join(" ")}>"

type ResultsException(Error)
doc ResultsException where only failures are stored
type FailuresException(ResultsException)

F init(re:ResultsException, msg:Str, results:Results) {
super(re, msg)
re.set('results', results)
}

doc Runs the computation and wraps the result: a value is wrapped in Success and an exception is wrapped in Failure.
doc %RET - Success or Failure
F Result(fun:Fun) {
try {
Success(fun())
} catch(e) {
Failure(e)
F init(re:ResultsException, msg:Str, results:Results) {
super(re, msg)
re.set('results', results)
}
}

doc Initialize Success with the given value.
F init(s:Success, v=null) s.val = v

doc Initialize Failure with the given value.
F init(f:Failure, e:Exception) f.val = e

doc Gets wrapped value
doc %RET - Any
doc %EX - { 1 / 10 }.Result().get() # 0
F get(s:Success) s.val

doc Throws ResultFail
doc %EX - { 1 / 0 }.Result().get() # ResultFail exception
F get(f:Failure) {
throw ResultFail("Can not get value of Failure", f.val)
}

doc Gets wrapped value
doc %RET - Any
doc %EX - { 1 / 10 }.Result().get(100) # 0
F get(s:Success, dflt) s.val

doc Returns dflt
doc %EX - { 1 / 0 }.Result().get(100) # 100
F get(f:Failure, dflt) dflt.Value()

doc %RET - s
F dflt(s:Success, x) s

doc %RET - Value(x,f)
F dflt(f:Failure, x) Success(x.Value(f))

TEST Success(1).dflt(2).get() == 1
TEST Failure(Error("test")).dflt(2).get() == 2

doc Run fun with wrapped value.
F each(s:Success, fun:Fun) {
fun(s.get())
s
}

doc Run fun with wrapped value. If exception is thrown, Failure is returned; otherwise Success with new value is returned.
doc %RET - Result
F map(s:Success, fun:Fun) Result({ fun(s.get()) })

doc No-op, returns f
doc %RET - f
F each(f:Failure, fun:Fun) f

doc No-op, returns f
doc %RET - f
F map(f:Failure, fun:Fun) f

doc Check whether wrapped value matches the pattern.
doc %RET - s or Failure
doc %EX - Success(10).filter(X>5) # <Success val=10>
doc %EX - Success(10).filter(X>15) # <Failure val=<ResultFail ...>>
F filter(s:Success, pattern=Bool.constructors) {
s.val =~ pattern returns s
Failure(ResultFail("Success filtered out, resulting Failure").set('pattern', pattern))
}

TEST Result({100}).filter() == Success(100)

doc No-op, returns f
doc %RET - f
doc %EX - Failure("blah").filter(X>5) # <Failure val=blah>
F filter(f:Failure, pattern=Bool.constructors) f

TEST Result({1/0}).filter() is Failure

doc Convert Success to Bool (true)
doc %RET - true
F Bool(s:Success) true

doc Convert Failure to Bool (false)
doc %RET - false
F Bool(f:Failure) false

doc EXPERIMENTAL! Do not use!
F ExitCode(r:Result) r.Bool().ExitCode()

TEST {read("/etc/passwd")}.Result() is Success
TEST {read("NO-SUCH-FILE")}.Result() is Failure
TEST Success(10).map(X*2).get() == 20
TEST { { throw Error("xx") }.Result().map(X*2).get() }.assert(ResultFail)

doc Convert Success into JSON compatible data structure - the value of the computation
F JsonData(s:Success) s.get().JsonData()

# === Diff =======================================

Expand Down Expand Up @@ -7246,7 +7262,9 @@ type SubSeq
doc Convert Success to FullBox
doc %RET - FullBox
doc %EX - Box("abcd" ~ /^(..)/).map({"First two letters: ${A[1]}"}).get("(too short)") # First two letters: ab
F Box(s:Success) FullBox(ms)
F Box(s:Success) FullBox(s.get())

TEST Box("abcd" ~ /^(..)/).map({"First two letters: ${A[1]}"}).get("(too short)") == "First two letters: ab"

doc Convert failure to EmptyBox
doc %RET - EmptyBox
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