Add json_map and json_set buildfile value types

These expose the std::map<json_value,json_value> and std::set<json_value>
types to buildfiles.

New functions:

  $size(<json-set>)
  $size(<json-map>)
  $keys(<json-map>)

Note that the $keys() function returns the list of map key as a json array.

For example:

m = [json_map] 2@([json] a@1 b@2) 1@([json] 1 2)
s = [json_set] ([json] x@1 y@2) ([json] a@1 b@2)

print ($m[2][b])              # 2
print ($s[([json] y@2 x@1)])  # true

3 files changed, 46 insertions, 2 deletions

diff --git a/tests/type/json/testscript b/tests/type/json/testscript
index 0e9af95..6dd6316 100644
--- a/tests/type/json/testscript
+++ b/tests/type/json/testscript
@@ -451,3 +451,47 @@
   abc
   EOO
 }
+
+: json-map
+:
+{
+  : basics
+  :
+  $* <<EOI >>EOO
+  m = [json_map] 2@([json] a@1 b@2) 1@([json] 1 2) 0@([json] null) -1@null
+  print $m
+  for p: $m
+    print $first($p) $second($p)
+  print ($m[1])
+  print $type($m[1])
+  print ($m[2][b])
+  EOI
+  -1@"" 0@"" 1@[1,2] 2@{"a":1,"b":2}
+  -1 ""
+  0 ""
+  1 [1,2]
+  2 {"a":1,"b":2}
+  [1,2]
+  json
+  2
+  EOO
+}
+
+: json-set
+:
+{
+  : basics
+  :
+  $* <<EOI >>EOO
+  s = [json_set] ([json] x@1 y@2) ([json] a@1 b@2)
+  print $s
+  for v: $s
+    print $type($v) $v
+  print ($s[([json] y@2 x@1)])
+  EOI
+  {"a":1,"b":2} {"x":1,"y":2}
+  json {"a":1,"b":2}
+  json {"x":1,"y":2}
+  true
+  EOO
+}
diff --git a/tests/type/map/testscript b/tests/type/map/testscript
index 1c6224a..29f5ed4 100644
--- a/tests/type/map/testscript
+++ b/tests/type/map/testscript
@@ -1,7 +1,7 @@
 # file      : tests/type/map/testscript
 # license   : MIT; see accompanying LICENSE file
 
-# See also tests in function/*/ (size(), keys()).
+# See also tests in function/*/ (size(), keys()), type/json/ (json_map).
 
 .include ../../common.testscript
 
diff --git a/tests/type/set/testscript b/tests/type/set/testscript
index da5e181..aca4c2d 100644
--- a/tests/type/set/testscript
+++ b/tests/type/set/testscript
@@ -1,7 +1,7 @@
 # file      : tests/type/set/testscript
 # license   : MIT; see accompanying LICENSE file
 
-# See also tests in function/*/ (size()).
+# See also tests in function/*/ (size()), type/json/ (json_set).
 
 .include ../../common.testscript