add trailing_zero option (#672)

README.md

@@ -327,6 +327,12 @@ funccall(
 * When set to `false`, the trailing comma is always removed during nesting.
 * When set to `nothing`, the trailing comma appears as it does in the original source.
 
+### `trailing_zero`
+
+> default: `true`
+
+Add a trailing zero, if needed.
+
 ### `join_lines_based_on_source`
 
 > default: `false`

src/JuliaFormatter.jl

@@ -87,6 +87,7 @@ function options(s::DefaultStyle)
         align_matrix = false,
         join_lines_based_on_source = false,
         trailing_comma = true,
+        trailing_zero = true,
         indent_submodule = false,
         separate_kwargs_with_semicolon = false,
         surround_whereop_typeparameters = true,
@@ -176,6 +177,7 @@ normalize_line_ending(s::AbstractString, replacer = WINDOWS_TO_UNIX) = replace(s
         normalize_line_endings = "auto",
         align_matrix::Bool = false,
         trailing_comma::Bool = false,
+        trailing_zero::Bool = true,
         indent_submodule::Bool = false,
         separate_kwargs_with_semicolon::Bool = false,
         surround_whereop_typeparameters::Bool = true,
@@ -485,6 +487,12 @@ value `"nothing"`:
 trailing_comma = "nothing"
 ```
 
+### `trailing_zero`
+
+> default: `true`
+
+Add a trailing zero, if needed.
+
 ### `join_lines_based_on_source`
 
 > default: `false`

src/options.jl

@@ -25,6 +25,7 @@ Base.@kwdef struct Options
     align_matrix::Bool = false
     join_lines_based_on_source::Bool = false
     trailing_comma::Union{Bool,Nothing} = true
+    trailing_zero::Bool = true
     indent_submodule::Bool = false
     separate_kwargs_with_semicolon::Bool = false
     surround_whereop_typeparameters::Bool = true

src/styles/blue/pretty.jl

@@ -54,6 +54,7 @@ function options(style::BlueStyle)
         align_matrix = false,
         join_lines_based_on_source = false,
         trailing_comma = true,
+        trailing_zero = true,
         surround_whereop_typeparameters = true,
     )
 end

src/styles/default/pretty.jl

@@ -369,32 +369,25 @@ end
 )
     loc = cursor_loc(s)
     if !is_str_or_cmd(cst)
-        val = cst.val
-
-        if val === nothing
-            return FST(LITERAL, loc[2], loc[1], loc[1], "")
-        end
+        (val = cst.val) === nothing && return FST(LITERAL, loc[2], loc[1], loc[1], "")
 
         if cst.head === :FLOAT
-            fidx = findlast(c -> c == 'f', val)
-            float_suffix = ""
-            if fidx !== nothing
+            if (fidx = findlast(==('f'), val)) === nothing
+                float_suffix = ""
+            else
                 float_suffix = val[fidx:end]
                 val = val[1:fidx-1]
             end
-
-            dotidx = findlast(c -> c == '.', val)
-
-            if fidx !== nothing && dotidx === nothing
-                # append a trailing zero prior to the float suffix
-                val *= ".0"
-            elseif dotidx == length(val)
-                # If a floating point ends in `.`, add trailing zero.
-                val *= '0'
-            elseif dotidx == 1
-                val = '0' * val
-            elseif dotidx == 2 && val[1] == '-'
-                val = val[1] * '0' * val[2:end]
+            if findfirst(c -> c == 'e' || c == 'E', val) === nothing
+                if (dotidx = findlast(==('.'), val)) === nothing
+                    val *= s.opts.trailing_zero ? ".0" : ""  # append a trailing zero prior to the suffix
+                elseif dotidx == length(val)
+                    val *= s.opts.trailing_zero ? "0" : ""  # if a float literal ends in `.`, add trailing zero.
+                elseif dotidx == 1
+                    val = '0' * val  # leading zero
+                elseif dotidx == 2 && (val[1] == '-' || val[1] == '+')
+                    val = val[1] * '0' * val[2:end]  # leading zero on signed numbers
+                end
             end
             val *= float_suffix
         end

src/styles/minimal/pretty.jl

@@ -14,6 +14,7 @@ function options(style::MinimalStyle)
         annotate_untyped_fields_with_any = false,
         join_lines_based_on_source = true,
         trailing_comma = nothing,
+        trailing_zero = false,
         margin = 10_000,
         always_for_in = nothing,
         whitespace_in_kwargs = false,

src/styles/sciml/pretty.jl

@@ -45,6 +45,7 @@ function options(style::SciMLStyle)
         align_pair_arrow = false,
         align_matrix = false,
         trailing_comma = true,
+        trailing_zero = true,
         indent_submodule = false,
         separate_kwargs_with_semicolon = false,
         surround_whereop_typeparameters = true,

src/styles/yas/pretty.jl

@@ -48,6 +48,7 @@ function options(style::YASStyle)
         normalize_line_endings = "auto",
         align_matrix = false,
         trailing_comma = true,
+        trailing_zero = true,
         indent_submodule = false,
         surround_whereop_typeparameters = true,
     )

test/options.jl

@@ -2310,4 +2310,14 @@
             for_in_replacement = "ni!",
         )
     end
+
+    @testset "trailing zero" begin
+        @test fmt("1e-2", trailing_zero = true) == "1e-2"
+        @test fmt("1f0", trailing_zero = true) == "1.0f0"
+        @test fmt("1.", trailing_zero = true) == "1.0"
+
+        @test fmt("1e-2", trailing_zero = false) == "1e-2"
+        @test fmt("1f0", trailing_zero = false) == "1f0"
+        @test fmt("1.", trailing_zero = false) == "1."
+    end
 end