String functions

Pipeline convention: in ${value | f x y} the left side is the FIRST argument, so this calls f(value, x, y). For example ${"hi" | upper} calls upper("hi").

upper

upper(value) → string

Converts the value’s string form to upper case.

Param	Type	Description
value	string	The string to upper-case (non-strings are formatted with %v first).

Examples

${"Hello" | upper}   → "HELLO"
${"aBc" | upper}     → "ABC"

lower

lower(value) → string

Converts the value’s string form to lower case.

Param	Type	Description
value	string	The string to lower-case (non-strings are formatted with %v first).

Examples

${"Hello" | lower}   → "hello"
${"aBc" | lower}     → "abc"

trim

trim(value) → string

Removes leading and trailing whitespace from the value’s string form.

Param	Type	Description
value	string	The string to trim.

Examples

${"  hi  " | trim}   → "hi"

trimPrefix

trimPrefix(value, prefix) → string

Removes prefix from the start of the string if present; otherwise returns the string unchanged. Errors if the prefix argument is missing.

Param	Type	Description
value	string	The string to operate on.
prefix	string	The prefix to remove.

Examples

${"foobar" | trimPrefix "foo"}   → "bar"
${"foobar" | trimPrefix "xyz"}   → "foobar"

trimSuffix

trimSuffix(value, suffix) → string

Removes suffix from the end of the string if present; otherwise returns the string unchanged. Errors if the suffix argument is missing.

Param	Type	Description
value	string	The string to operate on.
suffix	string	The suffix to remove.

Examples

${"foobar" | trimSuffix "bar"}   → "foo"
${"foobar" | trimSuffix "xyz"}   → "foobar"

replace

replace(value, old, new) → string

Replaces every non-overlapping occurrence of old with new. Errors if fewer than two arguments are supplied.

Param	Type	Description
value	string	The string to operate on.
old	string	Substring to search for.
new	string	Replacement substring.

Examples

${"a.b.c" | replace "." "-"}   → "a-b-c"
${"aaa" | replace "a" "bb"}    → "bbbbbb"

quote

quote(value) → string

Wraps the value’s string form in double quotes using Go’s %q formatting (escaping special characters).

Param	Type	Description
value	string	The string to quote.

Examples

${"Hello" | quote}   → "Hello" (with surrounding double quotes)

squote

squote(value) → string

Wraps the value’s string form in single quotes without any escaping.

Param	Type	Description
value	string	The string to single-quote.

Examples

${"Hello" | squote}   → 'Hello'

indent

indent(value, width) → string

Prepends width spaces to the beginning of every line. Errors if width is missing, non-numeric, negative, exceeds 65536, or if the result exceeds the internal output-size cap.

Param	Type	Description
value	string	The (possibly multi-line) string to indent.
width	int	Number of leading spaces per line; 0..65536.

Examples

${"a
b" | indent 2}
# →
  a
  b

${"x" | indent 0}   → "x"

nindent

nindent(value, width) → string

Like indent, but also prepends a leading newline before the first indented line. Same error conditions as indent.

Param	Type	Description
value	string	The (possibly multi-line) string to indent.
width	int	Number of leading spaces per line; 0..65536.

Examples (nindent prepends a leading newline, shown here as the blank first line)

${"a
b" | nindent 2}
# →

  a
  b

${"x" | nindent 4}
# →

    x

trunc

trunc(value, length) → string

Truncates the string to at most length runes; a negative length yields an empty string; a length at or beyond the rune count returns it unchanged. Errors if length is missing or non-numeric.

Param	Type	Description
value	string	The string to truncate.
length	int	Maximum number of runes to keep.

Examples

${"Hello" | trunc 3}    → "Hel"
${"Hello" | trunc 10}   → "Hello"
${"Hello" | trunc -1}   → ""

camelcase

camelcase(value) → string

Splits into words (on spaces, _, -, ., and lower→upper case boundaries) and joins them camelCase: first word lower-cased, each subsequent word capitalized.

Param	Type	Description
value	string	The string to convert.

Examples

${"hello world" | camelcase}   → "helloWorld"
${"foo_bar-baz" | camelcase}   → "fooBarBaz"
${"HelloWorld" | camelcase}    → "helloWorld"

kebabcase

kebabcase(value) → string

Splits into words and joins them lower-cased with hyphens.

Param	Type	Description
value	string	The string to convert.

Examples

${"Hello World" | kebabcase}   → "hello-world"
${"fooBar" | kebabcase}        → "foo-bar"

snakecase

snakecase(value) → string

Splits into words and joins them lower-cased with underscores.

Param	Type	Description
value	string	The string to convert.

Examples

${"Hello World" | snakecase}   → "hello_world"
${"fooBar" | snakecase}        → "foo_bar"

swapcase

swapcase(value) → string

Swaps the case of each letter; other characters are unchanged.

Param	Type	Description
value	string	The string to convert.

Examples

${"Hello World" | swapcase}   → "hELLO wORLD"
${"aBc123" | swapcase}        → "AbC123"

initials

initials(value) → string

Returns the first character of each whitespace-separated field, concatenated.

Param	Type	Description
value	string	The string whose word initials are collected.

Examples

${"Hello World Foo" | initials}     → "HWF"
${"john ronald tolkien" | initials} → "jrt"