Merge pull request #62 from sourceryinstitute/fix-example

fix(read-from-json): declare instead of associate

Author: rouson

README.md

@@ -13,11 +13,11 @@ DAG is based on a fork of [daglib by Jacob Williams], refactored to
 
 * Adopt a functional programming pattern based on (mostly) pure functions. 
 * Add build system and test harness automated by [fpm],
-* Add unit testing written with [Vegetables], 
+* Add unit testing written with [veggies], 
 * Add continuous-integration testing and documentation deployment via [GitHub Actions], 
 * Add [documentation] generated by [FORD], 
 * Add runtime assertion-checking using [Assert], and
-* Add [JSON] file input/output using [jsonff].
+* Add [JSON] file input/output using [rojff].
 * Ensure that dag objects always have a valid state that includes a topological
   ordering stored without mutating vertices or vertex arrays. 
 
@@ -85,8 +85,9 @@ fpm run --example print-to-json > dag.json
 * [read-from-json.f90] - constructs a DAG by reading from a JSON file.
   Run this example as follows:
 ```
-fpm run --example read-from-json > dag.json
+fpm run --example read-from-json
 ```
+which will read the file [./example/dag-dependencies.json]
 * [dag-to-dot.f90] - constructs a DAG describing the module dependencies in  
   an early version of the Framework for Extensible Asynchronous 
   Task Scheduling ([FEATS]) and prints the DAG to a .dot file suitable for
@@ -128,11 +129,11 @@ If you find this software useful, please consider donating code or
 [fpm]: https://github.com/fortran-lang/fpm
 [3276af]: https://github.com/everythingfunctional/fpm/commit/3276af2e000d1b2c90f151148cd01cce0d3e886d
 
-[Vegetables]: https://gitlab.com/everythingfunctional/Vegetables
+[veggies]: https://gitlab.com/everythingfunctional/veggies
 [GitHub Actions]: https://github.com/features/actions
 [FORD]: https://github.com/Fortran-FOSS-Programmers/ford
 [JSON]: https://www.json.org/json-en.html
-[jsonff]: https://gitlab.com/everythingfunctional/jsonff
+[rojff]: https://gitlab.com/everythingfunctional/rojff
 [./src/dag_test.f90]: ./src/dag_test.f90
 [example]: ./example/
 [FEATS]: https://github.com/sourceryinstitute/feats
@@ -142,3 +143,4 @@ If you find this software useful, please consider donating code or
 [dag-to-dot.f90]: ./example/dag-to-dot.f90
 [documentation]: https://sourceryinstitute.github.io/dag/
 [issue]: https://github.com/sourceryinstitute/dag/issues/new
+[./example/dag-dependencies.json]: ./example/dag-dependencies.json

example/read-from-json.f90

@@ -7,12 +7,13 @@ program read_from_json
   !!   fpm run --example read-from-json
   !!
   use dag_m, only: dag_t
-  use rojff, only : parse_json_from_file, json_object_t
+  use rojff, only : parse_json_from_file, json_object_t, fallible_json_value_t
   use iso_varying_string, only : char
   implicit none
+  type(fallible_json_value_t) parsed_json
 
 
-  associate(parsed_json => parse_json_from_file('example/dag-dependencies.json'))
+  parsed_json = parse_json_from_file('example/dag-dependencies.json')
 
     if (parsed_json%failed()) then
       error stop char(parsed_json%errors%to_string())
@@ -29,6 +30,4 @@ program read_from_json
       end select
     end block
 
-  end associate
-
 end program