## handling malformed programs container environment [ recipe-errors:text ] # copy code from recipe editor, persist to disk, load, save any errors def! update-recipes env:&:environment, resources:&:resources, screen:&:screen -> errors-found?:bool, env:&:environment, resources:&:resources, screen:&:screen [ local-scope load-inputs recipes:&:editor <- get *env, recipes:offset in:text <- editor-contents recipes resources <- dump resources, [lesson/recipes.mu], in recipe-errors:text <- reload in *env <- put *env, recipe-errors:offset, recipe-errors # if recipe editor has errors, stop { break-unless recipe-errors update-status screen, [errors found ], 1/red errors-found? <- copy true return } errors-found? <- copy false ] after [ old-recipe-errors:text <- get *env, recipe-errors:offset ] before [ # if there were recipe errors before, check if we can clear them { break-unless old-recipe-errors screen <- render-recipes screen, env, render } render-recipe-errors env, screen ] before [ row <- render-recipe-errors env, screen ] def render-recipe-errors env:&:environment, screen:&:screen -> row:num, screen:&:screen [ local-scope load-inputs recipe-errors:text <- get *env, recipe-errors:offset recipes:&:editor <- get *env, recipes:offset row:num <- get *recipes, bottom:offset row <- add row, 1 return-unless recipe-errors left:num <- get *recipes, left:offset right:num <- get *recipes, right:offset row, screen <- render-text screen, recipe-errors, left, right, 1/red, row # draw dotted line after recipes draw-horizontal screen, row, left, right, 9480/horizontal-dotted row <- add row, 1 clear-screen-from screen, row, left, left, right ] container environment [ error-index:num # index of first sandbox with an error (or -1 if none) ] after [ *result <- put *result, error-index:offset, -1 ] after [ *env <- put *env, error-index:offset, -1 ] before [ { error-index:num <- get *env, error-index:offset sandboxes-completed-successfully?:bool <- equal error-index, -1 break-if sandboxes-completed-successfully? errors-found? <- copy true } ] before [ { break-unless error? recipe-errors:text <- get *env, recipe-errors:offset break-if recipe-errors error-index:num <- get *env, error-index:offset sandboxes-completed-successfully?:bool <- equal error-index, -1 break-if sandboxes-completed-successfully? error-index-text:text <- to-text error-index status:text <- interpolate [errors found (_) ], error-index-text update-status screen, status, 1/red } ] container sandbox [ errors:text ] def! update-sandbox sandbox:&:sandbox, env:&:environment, idx:num -> sandbox:&:sandbox, env:&:environment [ local-scope load-inputs data:text <- get *sandbox, data:offset response:text, errors:text, fake-screen:&:screen, trace:text, completed?:bool <- run-sandboxed data *sandbox <- put *sandbox, response:offset, response *sandbox <- put *sandbox, errors:offset, errors *sandbox <- put *sandbox, screen:offset, fake-screen *sandbox <- put *sandbox, trace:offset, trace { break-if errors break-if completed? errors <- new [took too long! ] *sandbox <- put *sandbox, errors:offset, errors } { break-unless errors error-index:num <- get *env, error-index:offset error-not-set?:bool <- equal error-index, -1 break-unless error-not-set? *env <- put *env, error-index:offset, idx } ] # make sure we render any trace after [ { sandbox-errors:text <- get *sandbox, errors:offset break-unless sandbox-errors *sandbox <- put *sandbox, response-starting-row-on-screen:offset, 0 # no response row, screen <- render-text screen, sandbox-errors, left, right, 1/red, row # don't try to print anything more for this sandbox jump +render-sandbox-end } ] scenario run-shows-errors-in-get [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height assume-resources [ [lesson/recipes.mu] <- [ |recipe foo [| | get 123:num, foo:offset| |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo] render-all screen, env, render screen-should-contain [ . run (F4) . .recipe foo [ ┊foo . . get 123:num, foo:offset ┊─────────────────────────────────────────────────. .] ┊ . . ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] screen-should-contain [ . errors found run (F4) . .recipe foo [ ┊foo . . get 123:num, foo:offset ┊─────────────────────────────────────────────────. .] ┊ . . ┊ . .foo: unknown element 'foo' in container 'number' ┊ . .foo: first ingredient of 'get' should be a contai↩┊ . .ner, but got '123:num' ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] screen-should-contain-in-color 1/red, [ . errors found . . . . . . . . . .foo: unknown element 'foo' in container 'number' . .foo: first ingredient of 'get' should be a contai . .ner, but got '123:num' . . . ] ] scenario run-shows-errors-without-final-newline-in-recipe-side [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height assume-resources [ ] env:&:environment <- new-programming-environment resources, screen render-all screen, env, render assume-console [ type [recipe foo x [ ]] press F4 ] run [ event-loop screen, console, env, resources ] screen-should-contain [ . errors found run (F4) . .recipe foo x [ ┊ . .] ┊─────────────────────────────────────────────────. .foo: ingredient 'x' has no type ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] ] scenario run-updates-status-with-first-erroneous-sandbox [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height assume-resources [ ] env:&:environment <- new-programming-environment resources, screen, [] render-all screen, env, render assume-console [ left-click 3, 80 # create invalid sandbox 1 type [get foo, x:offset] press F4 # create invalid sandbox 0 type [get foo, x:offset] press F4 ] run [ event-loop screen, console, env, resources ] # status line shows that error is in first sandbox screen-should-contain [ . errors found (0) run (F4) . ] ] scenario run-updates-status-with-first-erroneous-sandbox-2 [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height assume-resources [ ] env:&:environment <- new-programming-environment resources, screen, [] render-all screen, env, render assume-console [ left-click 3, 80 # create invalid sandbox 2 type [get foo, x:offset] press F4 # create invalid sandbox 1 type [get foo, x:offset] press F4 # create valid sandbox 0 type [add 2, 2] press F4 ] run [ event-loop screen, console, env, resources ] # status line shows that error is in second sandbox screen-should-contain [ . errors found (1) run (F4) . ] ] scenario run-hides-errors-from-past-sandboxes [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height assume-resources [ ] env:&:environment <- new-programming-environment resources, screen, [get foo, x:offset] # invalid render-all screen, env, render assume-console [ press F4 # generate error ] event-loop screen, console, env, resources assume-console [ left-click 3, 58 press ctrl-k type [add 2, 2] # valid code press F4 # update sandbox ] run [ event-loop screen, console, env, resources ] # error should disappear screen-should-contain [ . run (F4) . . ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊─────────────────────────────────────────────────. . ┊0 edit copy to recipe delete . . ┊add 2, 2 . . ┊4 . . ┊─────────────────────────────────────────────────. . ┊ . ] ] scenario run-updates-errors-for-shape-shifting-recipes [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height # define a shape-shifting recipe with an error assume-resources [ [lesson/recipes.mu] <- [ |recipe foo x:_elem -> z:_elem [| | local-scope| | load-ingredients| | y:&:num <- copy null| | z <- add x, y| |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo 2] render-all screen, env, render assume-console [ press F4 ] event-loop screen, console, env, resources screen-should-contain [ . errors found (0) run (F4) . .recipe foo x:_elem -> z:_elem [ ┊ . . local-scope ┊─────────────────────────────────────────────────. . load-ingredients ┊0 edit copy to recipe delete . . y:&:num <- copy null ┊foo 2 . . z <- add x, y ┊foo_2: 'add' requires number ingredients, but go↩. .] ┊t 'y' . . ┊─────────────────────────────────────────────────. .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] # now rerun everything assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] # error should remain unchanged screen-should-contain [ . errors found (0) run (F4) . .recipe foo x:_elem -> z:_elem [ ┊ . . local-scope ┊─────────────────────────────────────────────────. . load-ingredients ┊0 edit copy to recipe delete . . y:&:num <- copy null ┊foo 2 . . z <- add x, y ┊foo_3: 'add' requires number ingredients, but go↩. .] ┊t 'y' . . ┊─────────────────────────────────────────────────. .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] ] scenario run-avoids-spurious-errors-on-reloading-shape-shifting-recipes [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height # overload a well-known shape-shifting recipe assume-resources [ [lesson/recipes.mu] <- [ |recipe length l:&:list:_elem -> n:num [| |]| ] ] # call code that uses other variants of it, but not it itself test-sandbox:text <- new [x:&:list:num <- copy null to-text x] env:&:environment <- new-programming-environment resources, screen, test-sandbox render-all screen, env, render # run it once assume-console [ press F4 ] event-loop screen, console, env, resources # no errors anywhere on screen (can't check anything else, since to-text will return an address) screen-should-contain-in-color 1/red, [ . . . . . . . . . <- . . . . . . . . . . . . . . . . . . . . . ] # rerun everything assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] # still no errors screen-should-contain-in-color 1/red, [ . . . . . . . . . <- . . . . . . . . . . . . . . . . . . . . . ] ] scenario run-shows-missing-type-errors [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height assume-resources [ [lesson/recipes.mu] <- [ |recipe foo [| | x <- copy 0| |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo] render-all screen, env, render assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] screen-should-contain [ . errors found run (F4) . .recipe foo [ ┊foo . . x <- copy 0 ┊─────────────────────────────────────────────────. .] ┊ . . ┊ . .foo: missing type for 'x' in 'x <- copy 0' ┊ . .foo: can't copy '0' to 'x'; types don't match ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] ] scenario run-shows-unbalanced-bracket-errors [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height # recipe is incomplete (unbalanced '[') assume-resources [ [lesson/recipes.mu] <- [ |recipe foo \\\[| | x <- copy 0| ] ] env:&:environment <- new-programming-environment resources, screen, [foo] render-all screen, env, render assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] screen-should-contain [ . errors found run (F4) . .recipe foo \\[ ┊foo . . x <- copy 0 ┊─────────────────────────────────────────────────. . ┊ . .9: unbalanced '\\[' for recipe ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] ] scenario run-shows-get-on-non-container-errors [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height assume-resources [ [lesson/recipes.mu] <- [ |recipe foo [| | local-scope| | x:&:point <- new point:type| | get x:&:point, 1:offset| |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo] render-all screen, env, render assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] screen-should-contain [ . errors found run (F4) . .recipe foo [ ┊foo . . local-scope ┊─────────────────────────────────────────────────. . x:&:point <- new point:type ┊ . . get x:&:point, 1:offset ┊ . .] ┊ . . ┊ . .foo: first ingredient of 'get' should be a contai↩┊ . .ner, but got 'x:&:point' ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] ] scenario run-shows-non-literal-get-argument-errors [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height assume-resources [ [lesson/recipes.mu] <- [ |recipe foo [| | local-scope| | x:num <- copy 0| | y:&:point <- new point:type| | get *y:&:point, x:num| |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo] render-all screen, env, render assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] screen-should-contain [ . errors found run (F4) . .recipe foo [ ┊foo . . local-scope ┊─────────────────────────────────────────────────. . x:num <- copy 0 ┊ . . y:&:point <- new point:type ┊ . . get *y:&:point, x:num ┊ . .] ┊ . . ┊ . .foo: second ingredient of 'get' should have type ↩┊ . .'offset', but got 'x:num' ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] ] scenario run-shows-errors-every-time [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height # try to run a file with an error assume-resources [ [lesson/recipes.mu] <- [ |recipe foo [| | local-scope| | x:num <- copy y:num| |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo] render-all screen, env, render assume-console [ press F4 ] event-loop screen, console, env, resources screen-should-contain [ . errors found run (F4) . .recipe foo [ ┊foo . . local-scope ┊─────────────────────────────────────────────────. . x:num <- copy y:num ┊ . .] ┊ . . ┊ . .foo: tried to read ingredient 'y' in 'x:num <- co↩┊ . .py y:num' but it hasn't been written to yet ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] # rerun the file, check for the same error assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] screen-should-contain [ . errors found run (F4) . .recipe foo [ ┊foo . . local-scope ┊─────────────────────────────────────────────────. . x:num <- copy y:num ┊ . .] ┊ . . ┊ . .foo: tried to read ingredient 'y' in 'x:num <- co↩┊ . .py y:num' but it hasn't been written to yet ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] ] scenario run-hides-errors [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 15/height # try to run a file with an error assume-resources [ [lesson/recipes.mu] <- [ |recipe foo [| | local-scope| | x:num <- copy y:num| |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo] render-all screen, env, render assume-console [ press F4 ] event-loop screen, console, env, resources screen-should-contain [ . errors found run (F4) . .recipe foo [ ┊foo . . local-scope ┊─────────────────────────────────────────────────. . x:num <- copy y:num ┊ . .] ┊ . . ┊ . .foo: tried to read ingredient 'y' in 'x:num <- co↩┊ . .py y:num' but it hasn't been written to yet ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] # fix the error, hit F4 assume-console [ left-click 3, 16 press ctrl-k type [0] press F4 ] event-loop screen, console, env, resources # no error anymore screen-should-contain [ . run (F4) . .recipe foo [ ┊ . . local-scope ┊─────────────────────────────────────────────────. . x:num <- copy 0 ┊0 edit copy to recipe delete . .] ┊foo . . ┊─────────────────────────────────────────────────. .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] ] scenario scrolling-recipe-side-reveals-errors [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 5/height # recipe overflows recipe side assume-resources [ [lesson/recipes.mu] <- [ |recipe foo [| | a:num <- copy 0| # padding to overflow recipe side | b:num <- copy 0| # padding to overflow recipe side | get 123:num, foo:offset| # line containing error |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo] render-all screen, env, render # hit F4, generating errors, then scroll down assume-console [ press F4 press page-down ] run [ event-loop screen, console, env, resources ] # errors should be displayed screen-should-contain [ . errors found run (F4) . . get 123:num, foo:offset ┊foo . .\\] ┊─────────────────────────────────────────────────. . ┊ . .foo: unknown element 'foo' in container 'number' ┊ . ] ] scenario run-instruction-and-print-errors [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 10/height assume-resources [ ] # sandbox editor contains an illegal instruction env:&:environment <- new-programming-environment resources, screen, [get 1234:num, foo:offset] render-all screen, env, render assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] # check that screen prints error message in red screen-should-contain [ . errors found (0) run (F4) . . ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊─────────────────────────────────────────────────. . ┊0 edit copy to recipe delete . . ┊get 1234:num, foo:offset . . ┊unknown element 'foo' in container 'number' . . ┊first ingredient of 'get' should be a container,↩. . ┊ but got '1234:num' . . ┊─────────────────────────────────────────────────. . ┊ . ] screen-should-contain-in-color 7/white, [ . . . . . . . . . get 1234:num, foo:offset . . . . . . . ] screen-should-contain-in-color 1/red, [ . errors found (0) . . . . . . . . . . unknown element 'foo' in container 'number' . . first ingredient of 'get' should be a container, . . but got '1234:num' . . . ] screen-should-contain-in-color 245/grey, [ . . . ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊─────────────────────────────────────────────────. . ┊ . . ┊ . . ┊ . . ┊ ↩. . ┊ . . ┊─────────────────────────────────────────────────. . ┊ . ] ] scenario run-instruction-and-print-errors-only-once [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 10/height assume-resources [ ] # sandbox editor contains an illegal instruction env:&:environment <- new-programming-environment resources, screen, [get 1234:num, foo:offset] render-all screen, env, render # run the code in the editors multiple times assume-console [ press F4 press F4 ] run [ event-loop screen, console, env, resources ] # check that screen prints error message just once screen-should-contain [ . errors found (0) run (F4) . . ┊ . .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊─────────────────────────────────────────────────. . ┊0 edit copy to recipe delete . . ┊get 1234:num, foo:offset . . ┊unknown element 'foo' in container 'number' . . ┊first ingredient of 'get' should be a container,↩. . ┊ but got '1234:num' . . ┊─────────────────────────────────────────────────. . ┊ . ] ] scenario sandbox-can-handle-infinite-loop [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 20/height # sandbox editor will trigger an infinite loop assume-resources [ [lesson/recipes.mu] <- [ |recipe foo [| | {| | loop| | }| |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo] render-all screen, env, render # run the sandbox assume-console [ press F4 ] run [ event-loop screen, console, env, resources ] screen-should-contain [ . errors found (0) run (F4) . .recipe foo [ ┊ . . { ┊─────────────────────────────────────────────────. . loop ┊0 edit copy to recipe delete . . } ┊foo . .] ┊took too long! . . ┊─────────────────────────────────────────────────. .┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┊ . . ┊ . ] ] scenario sandbox-with-errors-shows-trace [ local-scope trace-until 100/app # trace too long assume-screen 100/width, 10/height # generate a stash and a error assume-resources [ [lesson/recipes.mu] <- [ |recipe foo [| | local-scope| | a:num <- next-ingredient| | b:num <- next-ingredient| | stash [dividing by], b| | _, c:num <- divide-with-remainder a, b| | reply b| |]| ] ] env:&:environment <- new-programming-environment resources, screen, [foo 4, 0] render-all screen, env, render # run assume-console [ press F4 ] event-loop screen, console, env, resources # screen prints error message screen-should-contain [ . errors found (0) run (F4) . .recipe foo [ ┊ . . local-scope ┊─────────────────────────────────────────────────. . a:num <- next-ingredient ┊0 edit copy to recipe delete . . b:num <- next-ingredient ┊foo 4, 0 . . stash [dividing by], b ┊foo: divide by zero in '_, c:num <- divide-with-↩. . _, c:num <- divide-with-remainder a, b ┊remainder a, b' . . reply b ┊─────────────────────────────────────────────────. .] ┊ . . ┊ . ] # click on the call in the sandbox assume-console [ left-click 4, 55 ] run [ event-loop screen, console, env, resources ] # screen should expand trace screen-should-contain [ . errors found (0) run (F4) . .recipe foo [ ┊ . . local-scope ┊─────────────────────────────────────────────────. . a:num <- next-ingredient ┊0 edit copy to recipe delete . . b:num <- next-ingredient ┊foo 4, 0 . . stash [dividing by], b ┊dividing by 0 . . _, c:num <- divide-with-remainder a, b ┊14 instructions run . . reply b ┊foo: divide by zero in '_, c:num <- divide-with-↩. .] ┊remainder a, b' . . ┊─────────────────────────────────────────────────. ] ]