interp,repl: Improved eval and output interrupt

repl now rewrites query to do implicit display inside the sub eval.
This makes it possible to interrupt eval and output in a better and faster way.

Make JSON encoder fail early on errors.

Add more interrupt tests.

internal/colorjson/encoder.go

@@ -205,6 +205,10 @@ func (e *Encoder) encodeArray(vs []interface{}) {
 	e.writeByte('[', e.colors.Array)
 	e.depth += e.indent
 	for i, v := range vs {
+		if e.wErr != nil {
+			return
+		}
+
 		if i > 0 {
 			e.writeByte(',', e.colors.Array)
 		}
@@ -237,6 +241,10 @@ func (e *Encoder) encodeMap(vs map[string]interface{}) {
 		return kvs[i].key < kvs[j].key
 	})
 	for i, kv := range kvs {
+		if e.wErr != nil {
+			return
+		}
+
 		if i > 0 {
 			e.writeByte(',', e.colors.Object)
 		}

pkg/cli/test.exp

@@ -31,6 +31,13 @@ expect "123"
 send "\x03"
 expect "mp3> "
 
+# test interrupt multiple outputs implicit display
+send "range(100000)\n"
+expect "123"
+# ctrl-c
+send "\x03"
+expect "mp3> "
+
 # test interrupt big json output
 send "\[range(100000)\] | d\n"
 expect "123"
@@ -38,6 +45,13 @@ expect "123"
 send "\x03"
 expect "mp3> "
 
+# test interrupt big json output implicit display
+send "\[range(100000)\]\n"
+expect "123"
+# ctrl-c
+send "\x03"
+expect "mp3> "
+
 # test exit
 # ctrl-d
 send "\x04"

pkg/interp/eval.jq

@@ -17,6 +17,13 @@ def _eval_error_function_not_defined($name; $args):
     "function not defined: \($name)/\($args | length)"
   );
 
+# if catch_query . -> try (.) catch .catch_query
+# if input_query . -> .input_query | .
+# if ... | <.slurp.> -> .slurp({slurp: "<slurp>", slurp_args: [arg query ast], orig: orig query ast, rewrite: rewritten query})
+# else if .output_query -> . | .output_query
+#
+# ex ... | slurp -> <slurp>({...})
+# ex no slurp: . -> try (.input_query | . | .output_query) catch .catch_query
 def _eval_query_rewrite($opts):
   _query_fromtostring(
     ( . as $orig_query
@@ -35,10 +42,9 @@ def _eval_query_rewrite($opts):
         # try (1+1) catch vs try 1 + 1 catch
         _query_try(. | _query_query; $opts.catch_query)
       end
-    | _query_pipe(
-        $opts.input_query // _query_ident;
-        .
-      )
+    | if $opts.input_query then
+        _query_pipe($opts.input_query; .)
+      end
     | if $slurp then
         _query_func(
           $slurp;
@@ -61,6 +67,8 @@ def _eval_query_rewrite($opts):
             )
           ]
         )
+      elif $opts.output_query then
+        _query_pipe(.; $opts.output_query)
       end
     )
   );

pkg/interp/help.jq

@@ -194,5 +194,6 @@ def _help($arg0; $topic):
     ( _repl_slurp_eval($query.rewrite) as $outputs
     | "value help"
     , $outputs
+    | display
     )
   end;

pkg/interp/interp.go

@@ -918,6 +918,8 @@ func (i *Interp) Eval(ctx context.Context, c interface{}, expr string, opts Eval
 		// gojq ctx cancel will not return ok=false, just cancelled error
 		if !ok {
 			runCtxCancelFn()
+		} else if _, ok := v.(error); ok {
+			runCtxCancelFn()
 		}
 		return v, ok
 	})

pkg/interp/repl.jq

@@ -211,18 +211,26 @@ def _repl_on_compile_error:
     end
   | println
   );
-def _repl_eval($expr; on_error; on_compile_error; $slurps):
+def _repl_display:
+  display(_display_default_opts);
+def _repl_eval($expr; on_error; on_compile_error):
   eval(
     $expr;
-    { slurps: $slurps,
+    { slurps:
+        { repl: "_repl_slurp",
+          help: "_help_slurp",
+          slurp: "_slurp"
+        },
+      # input to repl is always array of values to iterate
       input_query: (_query_ident | _query_iter), # .[]
-      catch_query: _query_func("_repl_on_expr_error")
+      # each input should be evaluted separatel like with cli, so catch and just print errors
+      catch_query: _query_func("_repl_on_expr_error"),
+      # run display in sub eval so it can be interrupted
+      output_query: _query_func("_repl_display")
     };
     on_error;
     on_compile_error
   );
-def _repl_eval($expr; on_error; on_compile_error):
-  _repl_eval($expr; on_error; on_compile_error; null);
 
 # run read-eval-print-loop
 # input is array of inputs to iterate
@@ -242,17 +250,10 @@ def _repl($opts):
     );
   def _repl_loop:
     try
-      ( _display_default_opts as $default_opts
-      | _repl_eval(
-          _read_expr;
-          _repl_on_error;
-          _repl_on_compile_error;
-          { repl: "_repl_slurp",
-            help: "_help_slurp",
-            slurp: "_slurp"
-          }
-        )
-      | display($default_opts)
+      _repl_eval(
+        _read_expr;
+        _repl_on_error;
+        _repl_on_compile_error
       )
     catch
       if . == "interrupt" then empty