strings: Add @go.trim

Author: mbland

lib/strings

@@ -82,6 +82,23 @@ export __GO_STRINGS_VALIDATION_SKIP_CALLERS=2
   printf -v "$2" -- '%s' "${*:3}"
 }
 
+# Trims the leading and trailing whitespace from a string
+#
+# Arguments:
+#   var_name:  Name of the caller's variable containing the string to trim
+@go.trim() {
+  @go.validate_identifier_or_die 'Input/output variable name' "$1"
+  local __go_trim_input__="${!1}"
+
+  if [[ "$__go_trim_input__" =~ ^[[:space:]]+ ]]; then
+    __go_trim_input__="${__go_trim_input__#${BASH_REMATCH[0]}}"
+  fi
+  if [[ "$__go_trim_input__" =~ [[:space:]]+$ ]]; then
+    __go_trim_input__="${__go_trim_input__%${BASH_REMATCH[0]}}"
+  fi
+  printf -v "$1" -- '%s' "$__go_trim_input__"
+}
+
 # Determines the common prefix for a set of strings
 #
 # Will return the empty string for a single argument. This facilitates prefix

tests/strings/trim.bats

@@ -0,0 +1,64 @@
+#! /usr/bin/env bats
+
+load ../environment
+load helpers
+
+setup() {
+  test_filter
+}
+
+teardown() {
+  @go.remove_test_go_rootdir
+}
+
+@test "$SUITE: error if result variable name not a valid identifier" {
+  create_strings_test_script '@go.trim "invalid;"'
+  run "$TEST_GO_SCRIPT"
+  assert_failure
+
+  local err_msg='^Input/output variable name "invalid;" for @go.trim '
+  err_msg+='contains invalid identifier characters at:$'
+
+  assert_lines_match "$err_msg" \
+    "^  $TEST_GO_SCRIPT:[0-9] main$"
+}
+
+@test "$SUITE: empty string" {
+  create_strings_test_script 'declare result' \
+    '@go.trim "result"' \
+    'echo "$result"'
+  run "$TEST_GO_SCRIPT"
+  assert_success ''
+}
+
+@test "$SUITE: no leading or trailing space" {
+  create_strings_test_script 'declare result="foo bar"' \
+    '@go.trim "result"' \
+    'echo "$result"'
+  run "$TEST_GO_SCRIPT"
+  assert_success 'foo bar'
+}
+
+@test "$SUITE: trim leading space" {
+  create_strings_test_script 'declare result="  foo bar"' \
+    '@go.trim "result"' \
+    'echo "$result"'
+  run "$TEST_GO_SCRIPT"
+  assert_success 'foo bar'
+}
+
+@test "$SUITE: trim trailing space" {
+  create_strings_test_script 'declare result="foo bar  "' \
+    '@go.trim "result"' \
+    'echo "$result"'
+  run "$TEST_GO_SCRIPT"
+  assert_success 'foo bar'
+}
+
+@test "$SUITE: trim leading and trailing space" {
+  create_strings_test_script 'declare result="  foo bar  "' \
+    '@go.trim "result"' \
+    'echo "$result"'
+  run "$TEST_GO_SCRIPT"
+  assert_success 'foo bar'
+}