A virtual jailed shell environment for Go apps backed by an io/fs#FS.
fix(expand): single-space past last tab stop and wide-rune width
Implements GNU coreutils compatibility for expand:
- Past the last specified -t stop, each tab becomes a
single space rather than extrapolating with the last
interval
- East Asian Wide and Fullwidth runes count as two
columns via golang.org/x/text/width
The -i/--initial GNU extension is retained.
Refs: docs/posix2018/CONFORMANCE.md
Assisted-by: Claude Opus 4.7 via Claude Code
Signed-off-by: Xe Iaso <me@xeiaso.net>
+53
-10
+9
-8
command/internal/expand/expand.go
+9
-8
command/internal/expand/expand.go
···
10
10
"strings"
11
11
12
12
"github.com/pborman/getopt/v2"
13
+
"golang.org/x/text/width"
13
14
"mvdan.cc/sh/v3/interp"
14
15
"tangled.org/xeiaso.net/kefka/command"
15
16
)
···
118
119
return stop - column
119
120
}
120
121
}
121
-
if len(tabStops) >= 2 {
122
-
last := tabStops[len(tabStops)-1]
123
-
prev := tabStops[len(tabStops)-2]
124
-
interval := last - prev
125
-
steps := (column-last)/interval + 1
126
-
next := last + steps*interval
127
-
return next - column
122
+
return 1
123
+
}
124
+
125
+
func runeWidth(r rune) int {
126
+
switch width.LookupRune(r).Kind() {
127
+
case width.EastAsianWide, width.EastAsianFullwidth:
128
+
return 2
128
129
}
129
130
return 1
130
131
}
···
151
152
inLeading = false
152
153
}
153
154
result.WriteRune(r)
154
-
column++
155
+
column += runeWidth(r)
155
156
}
156
157
return result.String()
157
158
}
+44
-2
command/internal/expand/expand_test.go
+44
-2
command/internal/expand/expand_test.go
···
89
89
wantStdout: " end\n",
90
90
},
91
91
{
92
-
name: "explicit tab stops past last uses last interval",
92
+
name: "explicit tab stops past last become single space",
93
93
args: []string{"-t", "4,8"},
94
94
stdin: "a\t\t\tx\n",
95
-
wantStdout: "a" + strings.Repeat(" ", 11) + "x\n",
95
+
wantStdout: "a" + strings.Repeat(" ", 8) + "x\n",
96
+
},
97
+
{
98
+
name: "multi-stop several tabs past last each one space",
99
+
args: []string{"-t", "4,8"},
100
+
stdin: "12345678\t\t\tx\n",
101
+
wantStdout: "12345678 x\n",
102
+
},
103
+
{
104
+
name: "narrow rune counts as one column",
105
+
args: nil,
106
+
stdin: "λ\tx\n",
107
+
wantStdout: "λ" + strings.Repeat(" ", 7) + "x\n",
108
+
},
109
+
{
110
+
name: "wide rune counts as two columns",
111
+
args: nil,
112
+
stdin: "中\tx\n",
113
+
wantStdout: "中" + strings.Repeat(" ", 6) + "x\n",
114
+
},
115
+
{
116
+
name: "wide rune 日 counts as two columns",
117
+
args: nil,
118
+
stdin: "日\tx\n",
119
+
wantStdout: "日" + strings.Repeat(" ", 6) + "x\n",
120
+
},
121
+
{
122
+
name: "mixed narrow and wide runes",
123
+
args: nil,
124
+
stdin: "a中\tb\n",
125
+
wantStdout: "a中" + strings.Repeat(" ", 5) + "b\n",
126
+
},
127
+
{
128
+
name: "leading-only kefka extension preserves interior tabs after text",
129
+
args: []string{"-i"},
130
+
stdin: "leading\tword\ttrailing\n",
131
+
wantStdout: "leading\tword\ttrailing\n",
96
132
},
97
133
{
98
134
name: "leading-only short flag preserves interior tabs",
···
111
147
args: []string{"-i", "-t", "4"},
112
148
stdin: " \tfoo\tbar\n",
113
149
wantStdout: " foo\tbar\n",
150
+
},
151
+
{
152
+
name: "leading-only with space-then-tab leading and interior tab",
153
+
args: []string{"-i"},
154
+
stdin: " \tword\ttrailing\n",
155
+
wantStdout: " word\ttrailing\n",
114
156
},
115
157
{
116
158
name: "expand from file",