X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/b53c265b5c7825d7fb6bb672547c44d080459d71..f20cfa4a4481b9cf5bd644f482f9711dbe32a51d:/doc/doc-docbook/spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 958e7caf6..c40cf23f8 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -6742,6 +6742,25 @@ lookup types support only literal keys.
 the implicit key is the host's IP address rather than its name (see section
 &<<SECThoslispatsikey>>&).
 .next
+.new
+.cindex lookup json
+.cindex json "lookup type"
+.cindex JSON expansions
+&(json)&: The given file is a text file with a JSON structure.
+An element of the structure is extracted, defined by the search key.
+The key is a list of subelement selectors
+(colon-separated by default but changeable in the usual way)
+which are applied in turn to select smaller and smaller portions
+of the JSON structure.
+If a selector is numeric, it must apply to a JSON array; the (zero-based)
+nunbered array element is selected.
+Otherwise it must apply to a JSON object; the named element is selected.
+The final resulting element can be a simple JSON type or a JSON object
+or array; for the latter two a string-representation os the JSON
+is returned.
+For elements of type string, the returned value is de-quoted.
+.wen
+.next
 .cindex "linear search"
 .cindex "lookup" "lsearch"
 .cindex "lsearch lookup type"
@@ -9532,6 +9551,8 @@ The expanded <&'string1'&> must be of the form:
 The braces, commas and colons, and the quoting of the member name are required;
 the spaces are optional.
 Matching of the key against the member names is done case-sensitively.
+If a returned value is a JSON string, it retains its leading and
+trailing quotes.
 . XXX should be a UTF-8 compare
 
 The results of matching are handled as above.
@@ -9577,6 +9598,8 @@ apart from leading and trailing white space, which is ignored.
 
 Field selection and result handling is as above;
 there is no choice of field separator.
+If a returned value is a JSON string, it retains its leading and
+trailing quotes.
 
 
 .vitem &*${filter{*&<&'string'&>&*}{*&<&'condition'&>&*}}*&