3 files changed, 48 insertions, 2 deletions

diff --git a/tamer/Makefile.am b/tamer/Makefile.am
index 2cc502c..3248bc6 100644
--- a/tamer/Makefile.am
+++ b/tamer/Makefile.am
@@ -18,7 +18,7 @@
 
 .DELETE_ON_ERROR:
 
-.PHONY: all
+.PHONY: all fix fmt
 
 CARGO_BUILD_FLAGS=@CARGO_BUILD_FLAGS@
 
@@ -31,6 +31,12 @@ html-am:
 
 # note that 'cargo check' is something else; see 'cargo --help'
 test: check
-check-am:
+check-am: check-fmt
 	@CARGO@ test
 
+check-fmt:
+	@CARGO@ fmt -- --check
+
+fix: fmt
+fmt:
+	@CARGO@ fmt
diff --git a/tamer/README.md b/tamer/README.md
index 6d44f02..2d14ef4 100644
--- a/tamer/README.md
+++ b/tamer/README.md
@@ -47,3 +47,34 @@ $ ./configure CARGO_BUILD_FLAGS=--release && make
 $ ./configure && make
 $ ./configure CARGO_BUILD_FLAGS=--release && make CARGO_BUILD_FLAGS=
 ```
+
+
+## Hacking
+This section contains advice for those developing TAMER.
+
+
+### Running Tests
+Developers should be using test-driven development (TDD).  `make check` will
+run all necessary tests.
+
+
+### Code Format
+Rust provides `rustfmt` that can automatically format code for you.  This
+project mandates its use and therefore eliminates personal preference in
+code style (for better or worse).
+
+Formatting checks are run during `make check` and, on failure, will output
+the diff that would be applied if you ran `make fmt` (or `make fix`); this
+will run `cargo fmt` for you (and will use the binaries configured via
+`configure`).
+
+Since developers should be doing test-driven development (TDD) and therefore
+should be running `make check` frequently, the hope is that frequent
+feedback on formatting issues will allow developers to quickly adjust their
+habits to avoid triggering formatting errors at all.
+
+If you want to automatically fix formatting errors and then run tests:
+
+```sh
+$ make fmt check
+```
diff --git a/tamer/configure.ac b/tamer/configure.ac
index 9ed3526..350b77b 100644
--- a/tamer/configure.ac
+++ b/tamer/configure.ac
@@ -55,6 +55,15 @@ AX_COMPARE_VERSION([$rustc_version], [ge], [$rustc_ver_req],
 AC_ARG_VAR([CARGO_BUILD_FLAGS],
            [Flags to be passed to `cargo build' when invoked via Make])
 
+# Cargo commands may be available but not necessarily installed for the
+# active toolchain.  Let's check that.
+AC_MSG_CHECKING([whether cargo-fmt is available for active toolchain])
+AS_IF([cargo fmt --help &>/dev/null],
+      [AC_MSG_RESULT(yes)],
+      [AC_MSG_RESULT(no)
+       cargo fmt --help  # run again so user can see output
+       AC_MSG_ERROR([missing cargo-fmt for active toolchain])])
+
 AC_CONFIG_FILES([Makefile])
 
 AC_OUTPUT