diff options
Diffstat (limited to 'lib/pure/strformat.nim')
| -rw-r--r-- | lib/pure/strformat.nim | 158 |
1 files changed, 112 insertions, 46 deletions
diff --git a/lib/pure/strformat.nim b/lib/pure/strformat.nim index 3fedff07b..7d093ebb3 100644 --- a/lib/pure/strformat.nim +++ b/lib/pure/strformat.nim @@ -133,13 +133,14 @@ runnableExamples: An expression like `&"{key} is {value:arg} {{z}}"` is transformed into: -.. code-block:: nim + ```nim var temp = newStringOfCap(educatedCapGuess) temp.formatValue(key, "") temp.add(" is ") temp.formatValue(value, arg) temp.add(" {z}") temp + ``` Parts of the string that are enclosed in the curly braces are interpreted as Nim code. To escape a `{` or `}`, double it. @@ -263,6 +264,12 @@ The available floating point presentation types are: exponent notation. `G` General format. Same as `g` except it switches to `E` if the number gets to large. +`i` Complex General format. This is only supported for + complex numbers, which it prints using the mathematical + (RE+IMj) format. The real and imaginary parts are printed + using the general format `g` by default, but it is + possible to combine this format with one of the other + formats (e.g `jf`). (None) Similar to `g`, except that it prints at least one digit after the decimal point. ================= ==================================================== @@ -272,13 +279,14 @@ The available floating point presentation types are: Because of the well defined order how templates and macros are expanded, strformat cannot expand template arguments: -.. code-block:: nim + ```nim template myTemplate(arg: untyped): untyped = echo "arg is: ", arg echo &"--- {arg} ---" let x = "abc" myTemplate(x) + ``` First the template `myTemplate` is expanded, where every identifier `arg` is substituted with its argument. The `arg` inside the @@ -289,12 +297,13 @@ identifier that cannot be resolved anymore. The workaround for this is to bind the template argument to a new local variable. -.. code-block:: nim + ```nim template myTemplate(arg: untyped): untyped = block: let arg1 {.inject.} = arg echo "arg is: ", arg1 echo &"--- {arg1} ---" + ``` The use of `{.inject.}` here is necessary again because of template expansion order and hygienic templates. But since we generally want to @@ -313,8 +322,8 @@ help with readability, since there is only so much you can cram into single letter DSLs. ]## -import macros, parseutils, unicode -import strutils except format +import std/[macros, parseutils, unicode] +import std/strutils except format when defined(nimPreviewSlimSystem): import std/assertions @@ -472,50 +481,48 @@ proc parseStandardFormatSpecifier*(s: string; start = 0; raise newException(ValueError, "invalid format string, cannot parse: " & s[i..^1]) +proc toRadix(typ: char): int = + case typ + of 'x', 'X': 16 + of 'd', '\0': 10 + of 'o': 8 + of 'b': 2 + else: + raise newException(ValueError, + "invalid type in format string for number, expected one " & + " of 'x', 'X', 'b', 'd', 'o' but got: " & typ) + proc formatValue*[T: SomeInteger](result: var string; value: T; - specifier: string) = + specifier: static string) = ## Standard format implementation for `SomeInteger`. It makes little ## sense to call this directly, but it is required to exist ## by the `&` macro. - if specifier.len == 0: + when specifier.len == 0: result.add $value - return - let spec = parseStandardFormatSpecifier(specifier) - var radix = 10 - case spec.typ - of 'x', 'X': radix = 16 - of 'd', '\0': discard - of 'b': radix = 2 - of 'o': radix = 8 else: - raise newException(ValueError, - "invalid type in format string for number, expected one " & - " of 'x', 'X', 'b', 'd', 'o' but got: " & spec.typ) - result.add formatInt(value, radix, spec) + const + spec = parseStandardFormatSpecifier(specifier) + radix = toRadix(spec.typ) -proc formatValue*(result: var string; value: SomeFloat; specifier: string) = - ## Standard format implementation for `SomeFloat`. It makes little + result.add formatInt(value, radix, spec) + +proc formatValue*[T: SomeInteger](result: var string; value: T; + specifier: string) = + ## Standard format implementation for `SomeInteger`. It makes little ## sense to call this directly, but it is required to exist ## by the `&` macro. if specifier.len == 0: result.add $value - return - let spec = parseStandardFormatSpecifier(specifier) - - var fmode = ffDefault - case spec.typ - of 'e', 'E': - fmode = ffScientific - of 'f', 'F': - fmode = ffDecimal - of 'g', 'G': - fmode = ffDefault - of '\0': discard else: - raise newException(ValueError, - "invalid type in format string for number, expected one " & - " of 'e', 'E', 'f', 'F', 'g', 'G' but got: " & spec.typ) + let + spec = parseStandardFormatSpecifier(specifier) + radix = toRadix(spec.typ) + + result.add formatInt(value, radix, spec) +proc formatFloat( + result: var string, value: SomeFloat, fmode: FloatFormatMode, + spec: StandardFormatSpecifier) = var f = formatBiggestFloat(value, fmode, spec.precision) var sign = false if value >= 0.0: @@ -550,23 +557,83 @@ proc formatValue*(result: var string; value: SomeFloat; specifier: string) = else: result.add res +proc toFloatFormatMode(typ: char): FloatFormatMode = + case typ + of 'e', 'E': ffScientific + of 'f', 'F': ffDecimal + of 'g', 'G': ffDefault + of '\0': ffDefault + else: + raise newException(ValueError, + "invalid type in format string for number, expected one " & + " of 'e', 'E', 'f', 'F', 'g', 'G' but got: " & typ) + +proc formatValue*(result: var string; value: SomeFloat; specifier: static string) = + ## Standard format implementation for `SomeFloat`. It makes little + ## sense to call this directly, but it is required to exist + ## by the `&` macro. + when specifier.len == 0: + result.add $value + else: + const + spec = parseStandardFormatSpecifier(specifier) + fmode = toFloatFormatMode(spec.typ) + + formatFloat(result, value, fmode, spec) + +proc formatValue*(result: var string; value: SomeFloat; specifier: string) = + ## Standard format implementation for `SomeFloat`. It makes little + ## sense to call this directly, but it is required to exist + ## by the `&` macro. + if specifier.len == 0: + result.add $value + else: + let + spec = parseStandardFormatSpecifier(specifier) + fmode = toFloatFormatMode(spec.typ) + + formatFloat(result, value, fmode, spec) + +proc formatValue*(result: var string; value: string; specifier: static string) = + ## Standard format implementation for `string`. It makes little + ## sense to call this directly, but it is required to exist + ## by the `&` macro. + const spec = parseStandardFormatSpecifier(specifier) + var value = + when spec.typ in {'s', '\0'}: value + else: static: + raise newException(ValueError, + "invalid type in format string for string, expected 's', but got " & + spec.typ) + when spec.precision != -1: + if spec.precision < runeLen(value): + const precision = cast[Natural](spec.precision) + setLen(value, Natural(runeOffset(value, precision))) + + result.add alignString(value, spec.minimumWidth, spec.align, spec.fill) + proc formatValue*(result: var string; value: string; specifier: string) = ## Standard format implementation for `string`. It makes little ## sense to call this directly, but it is required to exist ## by the `&` macro. let spec = parseStandardFormatSpecifier(specifier) - var value = value - case spec.typ - of 's', '\0': discard - else: - raise newException(ValueError, - "invalid type in format string for string, expected 's', but got " & - spec.typ) + var value = + if spec.typ in {'s', '\0'}: value + else: + raise newException(ValueError, + "invalid type in format string for string, expected 's', but got " & + spec.typ) if spec.precision != -1: if spec.precision < runeLen(value): - setLen(value, runeOffset(value, spec.precision)) + let precision = cast[Natural](spec.precision) + setLen(value, Natural(runeOffset(value, precision))) + result.add alignString(value, spec.minimumWidth, spec.align, spec.fill) +proc formatValue[T: not SomeInteger](result: var string; value: T; specifier: static string) = + mixin `$` + formatValue(result, $value, specifier) + proc formatValue[T: not SomeInteger](result: var string; value: T; specifier: string) = mixin `$` formatValue(result, $value, specifier) @@ -663,8 +730,7 @@ proc strformatImpl(f: string; openChar, closeChar: char, strlit.add closeChar inc i, 2 else: - doAssert false, "invalid format string: '$1' instead of '$1$1'" % $closeChar - inc i + raiseAssert "invalid format string: '$1' instead of '$1$1'" % $closeChar else: strlit.add f[i] inc i |