implement JSON.object and JSON.keys

Author: perlpunk

ReadMe.pod

@@ -128,6 +128,17 @@ cache). The value (if any) is written to stdout.
 
 See FLAGS below for an explanation of the flag options.
 
+=item C<< JSON.keys <key-path> [<linear-var-name>] >>
+
+This function takes a key path and returns the keys of the corresponding
+object, one per line. If the key is not found or the value of the key is not
+an object, it will return nothing.
+
+=item C<< JSON.object <key-path> [<linear-var-name>] >>
+
+This function takes a key path and returns the corresponding object. If the
+key is not found, it will return nothing.
+
 =item C<< JSON.put [-s|-b|-n|-z] <key-path> <new-value> [<linear-var-name>] >>
 
 This function adds a path/value pair to the linear tree. If the path already

doc/json.swim

@@ -112,6 +112,17 @@ remove data from the linear form.
 
   See FLAGS below for an explanation of the flag options.
 
+- `JSON.keys <key-path> [<linear-var-name>]`
+
+  This function takes a key path and returns the keys of the corresponding
+  object, one per line. If the key is not found or the value of the
+  key is not an object, it will return nothing.
+
+- `JSON.object <key-path> [<linear-var-name>]`
+
+  This function takes a key path and returns the corresponding object.
+  If the key is not found, it will return nothing.
+
 - `JSON.put [-s|-b|-n|-z] <key-path> <new-value> [<linear-var-name>]`
 
   This function adds a path/value pair to the linear tree. If the path already

lib/json.bash

@@ -68,6 +68,44 @@ JSON.get() {
   esac
 }
 
+JSON.keys() {
+  if [[ $# -gt 2 ]]; then
+    JSON.die 'Usage: JSON.keys <key-path> [<tree-var>]'
+  fi
+  JSON.object "$@" |
+    cut -f1 |
+    sed "s/^\///; s/\/.*//" |
+    sort -u
+}
+
+JSON.object() {
+  case $# in
+    1)
+      JSON._object "$@"
+      ;;
+    2)
+      if [ "$2" == '-' ]; then
+        echo "$JSON__cache" | JSON._object "$@"
+      else
+        echo "${!2}" | JSON._object "$@"
+      fi
+      ;;
+    *)
+    JSON.die 'Usage: JSON.object <key-path> [<tree-var>]' ;;
+  esac
+}
+
+JSON._object() {
+  local key=$1
+  if [[ -n $key && $key != "/" ]]; then
+    key=${key/\//\\/}
+    grep -E "^$key/" |
+    sed "s/^$key//"
+  else
+    cat
+  fi
+}
+
 JSON.put() {
   set -o pipefail
   if [[ $# -gt 0 && $1 =~ ^-([snbz])$ ]]; then

man/man1/json.1

@@ -178,6 +178,14 @@ This function takes a key path and returns the corresponding value. If the key i
 With just the one required argument, the linear tree will be obtained from stdin. Otherwise it can be provided with a variable name (or \f(CW\*(C`\-\*(C'\fR for the cache). The value (if any) is written to stdout.
 .Sp
 See \s-1FLAGS\s0 below for an explanation of the flag options.
+.ie n .IP """JSON.keys <key\-path> [<linear\-var\-name>]""" 4
+.el .IP "\f(CWJSON.keys <key\-path> [<linear\-var\-name>]\fR" 4
+.IX Item "JSON.keys <key-path> [<linear-var-name>]"
+This function takes a key path and returns the keys of the corresponding object, one per line. If the key is not found or the value of the key is not an object, it will return nothing.
+.ie n .IP """JSON.object <key\-path> [<linear\-var\-name>]""" 4
+.el .IP "\f(CWJSON.object <key\-path> [<linear\-var\-name>]\fR" 4
+.IX Item "JSON.object <key-path> [<linear-var-name>]"
+This function takes a key path and returns the corresponding object. If the key is not found, it will return nothing.
 .ie n .IP """JSON.put [\-s|\-b|\-n|\-z] <key\-path> <new\-value> [<linear\-var\-name>]""" 4
 .el .IP "\f(CWJSON.put [\-s|\-b|\-n|\-z] <key\-path> <new\-value> [<linear\-var\-name>]\fR" 4
 .IX Item "JSON.put [-s|-b|-n|-z] <key-path> <new-value> [<linear-var-name>]"

test/keys.json

@@ -0,0 +1,14 @@
+{
+    "description": "description of gist",
+    "files": {
+        "file1.txt": {
+            "type": "text/plain",
+            "content": "two\nlines"
+        },
+        "file 2.txt": {
+            "type": "text/plain",
+            "content": "two\nlines"
+        }
+
+    }
+}

test/keys.t

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+
+source test/setup
+
+use Test::More tests 5
+use JSON
+
+tree1=$(cat test/keys.json | JSON.load)
+ok $?                           "JSON.load succeeded"
+
+is "$(JSON.get '/files/file 2.txt/type' tree1)" '"text/plain"' \
+                                "JSON.get works"
+
+file_object=$(JSON.object '/files' tree1)
+
+keys="$(JSON.keys '/' file_object)"
+
+is "$keys" "file1.txt"$'\n'"file 2.txt" \
+                                "JSON.keys '/'"
+
+keys="$(JSON.keys '/files' tree1)"
+is "$keys" "file1.txt"$'\n'"file 2.txt" \
+                                "JSON.keys 'files'"
+
+keys="$(JSON.keys '/' tree1)"
+is "$keys" "description"$'\n'"files" \
+                                "JSON.keys ''"