diff options
| -rw-r--r-- | lib/pure/strformat.nim | 38 | ||||
| -rw-r--r-- | tests/stdlib/tstrformat.nim | 24 | ||||
| -rw-r--r-- | tests/stdlib/tstrformatMissingFormatValue.nim | 16 |
3 files changed, 28 insertions, 50 deletions
diff --git a/lib/pure/strformat.nim b/lib/pure/strformat.nim index a8ceecf3d..e12ca3c89 100644 --- a/lib/pure/strformat.nim +++ b/lib/pure/strformat.nim @@ -102,7 +102,9 @@ of ``formatValue`` procs. The required signature for a type ``T`` that supports formatting is usually ``proc formatValue(result: var string; x: T; specifier: string)``. The subexpression after the colon -(``arg`` in ``&"{key} is {value:arg} {{z}}"``) is optional. It will be passed as the last argument to ``formatValue``. When the colon with the subexpression it is left out, an empty string will be taken instead. +(``arg`` in ``&"{key} is {value:arg} {{z}}"``) is optional. It will be passed as +the last argument to ``formatValue``. When the colon with the subexpression it is +left out, an empty string will be taken instead. For strings and numeric types the optional argument is a so-called "standard format specifier". @@ -215,8 +217,7 @@ Limitations =========== Because of the well defined order how templates and macros are -expanded, strformat cannot expand template arguments. - +expanded, strformat cannot expand template arguments: .. code-block:: nim template myTemplate(arg: untyped): untyped = @@ -233,27 +234,6 @@ quoted string literal. It is not an identifier yet. Then the strformat macro creates the ``arg`` identifier from the string literal. An identifier that cannot be resolved anymore. -.. code-block:: nim - let x = "abc" - myTemplate(x) - - # expansion of myTemplate - - let x = "abc" - echo "arg is: ", x - echo &"--- {arg} ---" - - # expansion of `&` - - let x = "abc" - echo "arg is: ", x - echo: - var temp = newStringOfCap(20) - temp.add "--- " - temp.formatValue arg, "" # arg cannot be resolved anymore - temp.add " ---" - temp - The workaround for this is to bind template argument to a new local variable. .. code-block:: nim @@ -265,11 +245,12 @@ The workaround for this is to bind template argument to a new local variable. echo &"--- {arg1} ---" The use of ``{.inject.}`` here is necessary again because of template -expansion order and hygienic templates. But since we generelly want to +expansion order and hygienic templates. But since we generally want to keep the hygienicness of ``myTemplate``, and we do not want ``arg1`` to be injected into the context where ``myTemplate`` is expanded, everything is wrapped in a ``block``. + Future directions ================= @@ -522,8 +503,9 @@ proc formatValue*(result: var string; value: string; specifier: string) = setLen(value, runeOffset(value, spec.precision)) result.add alignString(value, spec.minimumWidth, spec.align, spec.fill) -template formatValue[T: enum](result: var string; value: T; specifier: string) = - result.add $value +proc formatValue[T](result: var string; value: T; specifier: string) = + mixin `$` + formatValue(result, $value, specifier) template formatValue(result: var string; value: char; specifier: string) = result.add value @@ -531,7 +513,7 @@ template formatValue(result: var string; value: char; specifier: string) = template formatValue(result: var string; value: cstring; specifier: string) = result.add value -proc formatValue[T](result: var string; value: openarray[T]; specifier: string) = +proc formatValue(result: var string; value: (array|seq|openArray); specifier: string) = result.add "[" for i, it in value: if i != 0: diff --git a/tests/stdlib/tstrformat.nim b/tests/stdlib/tstrformat.nim index d99aeb2f1..86125ca00 100644 --- a/tests/stdlib/tstrformat.nim +++ b/tests/stdlib/tstrformat.nim @@ -1,5 +1,6 @@ discard """ action: "run" +output: '''Received (name: "Foo", species: "Bar")''' """ import strformat @@ -64,16 +65,14 @@ doAssert fmt"{0.0: g}" == " 0" let data1 = [1'i64, 10000'i64, 10000000'i64] let data2 = [10000000'i64, 100'i64, 1'i64] -doAssert fmt"data1: {data1:8} ∨" == "data1: [ 1, 10000, 10000000] ∨" -doAssert fmt"data2: {data2:8} ∧" == "data2: [10000000, 100, 1] ∧" +doAssert fmt"data1: {data1:8} #" == "data1: [ 1, 10000, 10000000] #" +doAssert fmt"data2: {data2:8} =" == "data2: [10000000, 100, 1] =" # custom format Value type Vec2[T] = object x,y: T - Vec2f = Vec2[float32] - Vec2i = Vec2[int32] proc formatValue[T](result: var string; value: Vec2[T]; specifier: string) = result.add '[' @@ -82,8 +81,8 @@ proc formatValue[T](result: var string; value: Vec2[T]; specifier: string) = result.formatValue value.y, specifier result.add "]" -let v1 = Vec2f(x:1.0, y: 2.0) -let v2 = Vec2i(x:1, y: 1337) +let v1 = Vec2[float32](x:1.0, y: 2.0) +let v2 = Vec2[int32](x:1, y: 1337) doAssert fmt"v1: {v1:+08} v2: {v2:>4}" == "v1: [+0000001, +0000002] v2: [ 1, 1337]" # issue #7632 @@ -94,3 +93,16 @@ doAssert works(5) == "formatted 5" doAssert fails0(6) == "formatted 6" doAssert fails(7) == "formatted 7" doAssert fails2[0](8) == "formatted 8" + + +# bug #11012 + +type + Animal = object + name, species: string + AnimalRef = ref Animal + +proc print_object(animalAddr: AnimalRef) = + echo fmt"Received {animalAddr[]}" + +print_object(AnimalRef(name: "Foo", species: "Bar")) diff --git a/tests/stdlib/tstrformatMissingFormatValue.nim b/tests/stdlib/tstrformatMissingFormatValue.nim deleted file mode 100644 index 66c1c8772..000000000 --- a/tests/stdlib/tstrformatMissingFormatValue.nim +++ /dev/null @@ -1,16 +0,0 @@ -discard """ -errormsg: '''type mismatch: got <string, Obj, string>''' -nimout: '''proc formatValue''' -""" - -# This test is here to make sure that there is a clean error that -# that indicates ``formatValue`` needs to be overloaded with the custom type. - -import strformat - -type Obj = object - -proc `$`(o: Obj): string = "foobar" - -var o: Obj -doAssert fmt"{o}" == "foobar" |