add is_empty to generator exported functions

bin/generate-spec

@@ -48,7 +48,7 @@ included_tests_from_toml = (path) ->
 
 -- ----------------------------------------------------------
 -- functions marked as global so spec_generators can see them
-export indent, quote, is_json_null
+export indent, quote, is_json_null, is_empty
 
 indent = (text, level) -> string.rep('  ', level) .. text
 
@@ -58,8 +58,10 @@ quote = (str) ->
   else
     "'#{str}'"
 
+is_empty = (t) -> not next t
+
 -- the dkjson `json.null` value is an empty table
-is_json_null = (value) -> type(value) == 'table' and #value == 0
+is_json_null = (value) -> type(value) == 'table' and is_empty(value)
 
 -- ----------------------------------------------------------
 

exercises/practice/matching-brackets/.meta/example.moon

@@ -1,8 +1,8 @@
 push     = table.insert
 pop      = table.remove
-is_empty = (s) -> #s == 0
+is_empty = (t) -> not next t
 
-opener   = { [']']: '[', ['}']: '{', [')']: '(' }
+opener   = ']':'[', '}':'{', ')':'('
 
 
 {

exercises/practice/proverb/.meta/spec_generator.moon

@@ -4,7 +4,7 @@
   generate_test: (case, level) ->
     input = table.concat [quote word for word in *case.input.strings], ', '
     local expected
-    if #case.expected == 0
+    if is_empty case.expected
       expected = "''"
     else
       expected = "[[\n#{table.concat case.expected, '\n'}\n]]"

exercises/test_helpers.md

@@ -1,5 +1,14 @@
 # Reusable stuff for spec generators
 
+## Functions in generate-spec script
+
+These functions are exported from generate-spec for use in spec_generator modules
+
+- `indent(text, level)` -- provide leading whitespace to the appropriate level.
+- `quote(str)` -- add quotation marks to the string, single or double as appropriate.
+- `is_empty(tbl)` -- predicate: is the table empty
+- `is_json_null(value)` -- predicate: is the value `json.null` from dkjson
+
 ## Helper functions
 
 Useful for generating pretty tables mostly.