fix: redo reverted commit 79baac with corrections

Author: Damian Rouson

README.md

@@ -18,44 +18,53 @@ DAG is based on a fork of [daglib by Jacob Williams], refactored to
 * Add ocumentation generated by [FORD], 
 * Add runtime assertion-checking using [Assert], and
 * Add [JSON] file input/output using [jsonff].
-* Ensure that DAG objects always have a valid state that includes a topolical ordering stored without mutating vertices or vertex arrays. 
+* Ensure that dag objects always have a valid state that includes a topological
+  ordering stored without mutating vertices or vertex arrays. 
 
 Usage
 -----
-When compilers cooperate, we recommend using `associate` to assign names to dag's user-defined
-structure constructor results.  See the [example] subdirectory for demonstrations of how we 
-use `associate` instead of the declare-and-define style that is much more common in Fortran 
-and other imperative programming languages.  Associating a name instead of declaring an object
-and then later defining it offers several potential advantages:
+When compilers cooperate, we recommend using `associate` to assign names to
+dag's user-defined structure constructor results.  See the [example]
+subdirectory for demonstrations of how we use `associate` instead of the
+declare-and-define style that is much more common in Fortran
+and other imperative programming languages.  Associating a name instead of
+declaring an object and then later defining it offers several potential
+advantages:
 
 * It prevents the accidental use of declared-but-undefined data.
 * It provides immutable state, which in turn
   - prevents the mistaken overwriting of data and
   - enables some possible compiler optimizations.
 
-Caveat emptor: your mileage may vary.  Compiler support for `associate` is evolving and
-compiler might or might not exploit optimizatio opportunities.  When weird things happen,
-resort to declaring and subsequently defining objects by assigning a constructor function
-result to the declared object.
+_Caveat emptor_: your mileage may vary.  Compiler support for `associate` is
+evolving and compiler might or might not exploit optimizatio opportunities.
+When weird things happen, resort to declaring and subsequently defining
+objects by assigning a constructor function result to the declared object.
 
 Prerequisites
 -------------
-The [fpm] package manager automatically downloads and builds all dependencies.
-See [fpm.toml] for a complete list, including version numbers.
+The [fpm] package manager automatically downloads and builds all
+dependencies.  See [fpm.toml] for a complete list, including version numbers.
+
+Downloading
+-----------
+Obtain dag by downloading the [latest release] or cloning the repository as
+follows:
 
-Downloading, building and testing
---------------------
-With [fpm]  installed, clone
 ```
 git clone [email protected]:sourceryinstitute/dag
 ```
-### Serial build and testing
-Build and test the `dag` library  with in a `bash`-like shell as follows:
+
+Building and testing
+--------------------
+### Building and testing for serial execution
+Build and test `dag` in a `bash`-like shell as follows:
 ```
 fpm test
 ```
-### Parallel building and testing with the gfortran/OpenCoarrays
-Build and test the `dag` library  with in a `bash`-like shell as follows:
+### Building and testing for parallel execution
+With [gfortran] and [OpenCoarrays] installed, build and test `dag` in a
+`bash`-like shell as follows:
 ```
 fpm test --compiler caf --runner "cafrun -n 2"
 ```
@@ -66,7 +75,6 @@ Please report any test failures by submitting an [issue] on the DAG repository.
 
 Examples
 --------
-
 The [example] subdirectory provides the following examples:
 
 * [print-to-json.f90] - constructs and prints it a JSON representation the DAG.