diff options
Diffstat (limited to 'jsonpath.h')
| -rw-r--r-- | jsonpath.h | 24 |
1 files changed, 24 insertions, 0 deletions
@@ -3,6 +3,16 @@ * jsonpath.h * JSONPath implementation routines for JSON data type support. * + * The "JSONPath" implemented here is similar to, but not exactly the same as, + * the JSONPath described at http://goessner.net/articles/JsonPath/ . + * The main differences are stronger subscripting rules, special methods + * via function-call notation (currently, the only one provided is .char()), + * and that the '$' at the beginning of a JSONPath expression is optional. + * Also, array indices as a set (e.g. [0,1]) and filters/scripts are currently + * not implemented. Array indices are a planned feature. True filters + * would require an honest-to-goodness JavaScript engine, so perhaps + * someone will write a module for that in the future. + * * Copyright (c) 2010, PostgreSQL Global Development Group * Written by Joey Adams <joeyadams3.14159@gmail.com>. * @@ -25,6 +35,13 @@ typedef enum JP_CALL_CHAR } jp_element_type; +/* + * A jp_element is a single piece of a JSONPath expression + * (e.g. [3], .foo, .char(3), ..*). It represents subscripting + * down one level in a JSON tree, or invoking a special method + * (like .char() ). However, if recursive_descent is set to true, + * the subscript applies to a value and all of its descendants. + */ typedef struct { jp_element_type type; @@ -49,6 +66,13 @@ typedef enum JP_REF_CHAR } JPRefType; +/* + * A JPRef is a reference to some part of a JSON tree, + * typically a value (but not always). + * + * JPRef* is really a "subclass" of JSON* . In the future, this structure + * will likely be merged into the JSON structure to improve performance. + */ typedef struct { JPRefType type; |