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Repr v2 progress (#13268)
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* progress on repr_v2

* repr progress

* add ref objects with distrinct

* fix failing tests
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cooldome authored and Araq committed Jan 28, 2020
1 parent 92010be commit 76ede7c
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Showing 4 changed files with 96 additions and 77 deletions.
7 changes: 2 additions & 5 deletions lib/system.nim
Original file line number Diff line number Diff line change
Expand Up @@ -1988,10 +1988,6 @@ template unlikely*(val: bool): bool =
import system/dollars
export dollars

when defined(nimV2):
import system/repr_v2
export repr_v2

const
NimMajor* {.intdefine.}: int = 1
## is the major number of Nim's version.
Expand Down Expand Up @@ -2620,7 +2616,8 @@ type
## Represents a Nim AST node. Macros operate on this type.

when defined(nimV2):
proc repr*(x: NimNode): string {.magic: "Repr", noSideEffect.}
import system/repr_v2
export repr_v2

macro lenVarargs*(x: varargs[untyped]): int {.since: (1, 1).} =
## returns number of variadic arguments in `x`
Expand Down
130 changes: 59 additions & 71 deletions lib/system/repr_v2.nim
Original file line number Diff line number Diff line change
@@ -1,3 +1,11 @@
proc isNamedTuple(T: typedesc): bool {.magic: "TypeTrait".}
## imported from typetraits

proc distinctBase(T: typedesc): typedesc {.magic: "TypeTrait".}
## imported from typetraits

proc repr*(x: NimNode): string {.magic: "Repr", noSideEffect.}

proc repr*(x: int): string {.magic: "IntToStr", noSideEffect.}
## repr for an integer argument. Returns `x`
## converted to a decimal string.
Expand Down Expand Up @@ -37,80 +45,68 @@ proc repr*[Enum: enum](x: Enum): string {.magic: "EnumToStr", noSideEffect.}
## If a `repr` operator for a concrete enumeration is provided, this is
## used instead. (In other words: *Overwriting* is possible.)

template repr(t: typedesc): string = $t

proc isNamedTuple(T: typedesc): bool =
# Taken from typetraits.
when T isnot tuple: result = false
proc repr*(p: pointer): string =
## repr of pointer as its hexadecimal value
if p == nil:
result = "nil"
else:
var t: T
for name, _ in t.fieldPairs:
when name == "Field0":
return compiles(t.Field0)
else:
return true
return false
when nimvm:
result = "ptr"
else:
const HexChars = "0123456789ABCDEF"
const len = sizeof(pointer) * 2
var n = cast[uint](p)
result = newString(len)
for j in countdown(len-1, 0):
result[j] = HexChars[n and 0xF]
n = n shr 4

proc repr*[T: tuple|object](x: T): string =
## Generic `repr` operator for tuples that is lifted from the components
## of `x`. Example:
##
## .. code-block:: Nim
## $(23, 45) == "(23, 45)"
## $(a: 23, b: 45) == "(a: 23, b: 45)"
## $() == "()"
when T is object:
result = $typeof(x)
else:
result = ""
result.add '('
template repr*(x: distinct): string =
repr(distinctBase(typeof(x))(x))

template repr*(t: typedesc): string = $t

proc reprObject[T: tuple|object](res: var string, x: T) =
res.add '('
var firstElement = true
const isNamed = T is object or isNamedTuple(T)
when not isNamed:
var count = 0
for name, value in fieldPairs(x):
if not firstElement: result.add(", ")
if not firstElement: res.add(", ")
when isNamed:
result.add(name)
result.add(": ")
res.add(name)
res.add(": ")
else:
count.inc
when compiles($value):
when value isnot string and value isnot seq and compiles(value.isNil):
if value.isNil: result.add "nil"
else: result.addQuoted(value)
else:
result.addQuoted(value)
firstElement = false
else:
result.add("...")
firstElement = false
res.add repr(value)
firstElement = false
when not isNamed:
if count == 1:
result.add(',') # $(1,) should print as the semantically legal (1,)
result.add(')')
res.add(',') # $(1,) should print as the semantically legal (1,)
res.add(')')


proc repr*[T: (ref object)](x: T): string =
proc repr*[T: tuple|object](x: T): string =
## Generic `repr` operator for tuples that is lifted from the components
## of `x`.
if x == nil: return "nil"
result = $typeof(x) & "("
var firstElement = true
for name, value in fieldPairs(x[]):
if not firstElement: result.add(", ")
result.add(name)
result.add(": ")
when compiles($value):
when value isnot string and value isnot seq and compiles(value.isNil):
if value.isNil: result.add "nil"
else: result.addQuoted(value)
else:
result.addQuoted(value)
firstElement = false
else:
result.add("...")
firstElement = false
result.add(')')
## of `x`. Example:
##
## .. code-block:: Nim
## $(23, 45) == "(23, 45)"
## $(a: 23, b: 45) == "(a: 23, b: 45)"
## $() == "()"
when T is object:
result = $typeof(x)
reprObject(result, x)

proc repr*[T](x: ptr T): string =
result.add repr(pointer(x)) & " "
result.add repr(x[])

proc repr*[T](x: ref T | ptr T): string =
if isNil(x): return "nil"
result = $typeof(x)
reprObject(result, x[])

proc collectionToRepr[T](x: T, prefix, separator, suffix: string): string =
result = prefix
Expand All @@ -120,15 +116,7 @@ proc collectionToRepr[T](x: T, prefix, separator, suffix: string): string =
firstElement = false
else:
result.add(separator)

when value isnot string and value isnot seq and compiles(value.isNil):
# this branch should not be necessary
if value.isNil:
result.add "nil"
else:
result.addQuoted(value)
else:
result.addQuoted(value)
result.add repr(value)
result.add(suffix)

proc repr*[T](x: set[T]): string =
Expand All @@ -153,9 +141,9 @@ proc repr*[T, U](x: HSlice[T, U]): string =
##
## .. code-block:: Nim
## $(1 .. 5) == "1 .. 5"
result = $x.a
result = repr(x.a)
result.add(" .. ")
result.add($x.b)
result.add(repr(x.b))

proc repr*[T, IDX](x: array[IDX, T]): string =
## Generic `repr` operator for arrays that is lifted from the components.
Expand Down
34 changes: 34 additions & 0 deletions tests/arc/trepr.nim
Original file line number Diff line number Diff line change
@@ -0,0 +1,34 @@
discard """
cmd: "nim c --gc:arc $file"
nimout: '''(a: true, n: doAssert)
Table[system.string, trepr.MyType](data: @[], counter: 0)
nil
'''
"""
import tables

type
NimSym = distinct NimNode
MyType = tuple
a: bool
n: NimSym

proc myproc(t: MyType) =
echo repr(t)

proc myproc2(t: MyType) =
var x = Table[string, t]()
echo repr(x)

proc myproc3(t: MyType) =
var x: TableRef[string, t]
echo repr(x)


macro dumpSym(a: typed) =
myproc((a: true, n: NimSym(a)))
myproc2((a: true, n: NimSym(a)))
myproc3((a: true, n: NimSym(a)))

dumpSym(doAssert)

2 changes: 1 addition & 1 deletion tests/destructor/tfinalizer.nim
Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
discard """
cmd: "nim c --gc:arc $file"
output: '''Foo(field: "Dick Laurent", k: ka, x: 0.0)
output: '''Foo(field: Dick Laurent, k: ka, x: 0.0)
Nobody is dead
Dick Laurent is dead'''
"""
Expand Down

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