From 854cf2a6badd8597b9d17c21d52e7cf5c6e0b767 Mon Sep 17 00:00:00 2001
From: Dov Murik <dov.murik@gmail.com>
Date: Mon, 14 Dec 2015 08:50:27 -0500
Subject: [PATCH] Makefile: add REPL invocation rules

---
 Makefile  | 20 ++++++++++++++++++++
 README.md | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/Makefile b/Makefile
index 5e1efd8b..389c9d89 100644
--- a/Makefile
+++ b/Makefile
@@ -184,6 +184,11 @@ DOCKER_BUILD = $(foreach impl,$(DO_IMPLS),docker-build^$(impl))
 
 IMPL_PERF = $(filter-out $(EXCLUDE_PERFS),$(foreach impl,$(DO_IMPLS),perf^$(impl)))
 
+IMPL_REPL = $(foreach impl,$(DO_IMPLS),repl^$(impl))
+ALL_REPL = $(strip $(sort \
+             $(foreach impl,$(DO_IMPLS),\
+               $(foreach step,$(STEPS),repl^$(impl)^$(step)))))
+
 #
 # Build rules
 #
@@ -264,3 +269,18 @@ $(IMPL_PERF):
           $(call $(impl)_RUNSTEP,stepA,$(call $(impl)_STEP_TO_PROG,stepA),../tests/perf2.mal); \
 	  echo 'Running: $(call $(impl)_RUNSTEP,stepA,$(call $(impl)_STEP_TO_PROG,stepA),../tests/perf3.mal)'; \
           $(call $(impl)_RUNSTEP,stepA,$(call $(impl)_STEP_TO_PROG,stepA),../tests/perf3.mal))
+
+# REPL invocation rules
+# Allow repl^IMPL^STEP and repl^IMPL (which starts REPL of stepA)
+
+.SECONDEXPANSION:
+$(IMPL_REPL): $$@^stepA
+
+.SECONDEXPANSION:
+$(ALL_REPL): $$(call $$(word 2,$$(subst ^, ,$$(@)))_STEP_TO_PROG,$$(word 3,$$(subst ^, ,$$(@))))
+	@$(foreach impl,$(word 2,$(subst ^, ,$(@))),\
+	  $(foreach step,$(word 3,$(subst ^, ,$(@))),\
+	    cd $(if $(filter mal,$(impl)),$(MAL_IMPL),$(impl)); \
+	    echo 'REPL implementation $(impl), step file: $+'; \
+	    echo 'Running: $(call $(impl)_RUNSTEP,$(step),$(+))'; \
+	    $(call $(impl)_RUNSTEP,$(step),$(+));))
diff --git a/README.md b/README.md
index 2051cc95..dc9e46f8 100644
--- a/README.md
+++ b/README.md
@@ -651,6 +651,39 @@ make MAL_IMPL=ruby "test^mal^step2"
 make MAL_IMPL=python "test^mal^step2"
 ```
 
+### Starting the REPL
+
+* To start the REPL of an implementation in a specific step:
+
+```
+make "repl^IMPL^stepX"
+
+# e.g
+make "repl^ruby^step3"
+make "repl^ps^step4"
+```
+
+* If you omit the step, then `stepA` is used:
+
+```
+make "repl^IMPL"
+
+# e.g
+make "repl^ruby"
+make "repl^ps"
+```
+
+* To start the REPL of the self-hosted implementation, specify `mal` as the
+  REPL implementation and use the `MAL_IMPL` make variable to change the
+  underlying host language (default is JavaScript):
+```
+make MAL_IMPL=IMPL "repl^mal^stepX"
+
+# e.g.
+make "repl^mal^step2"   # js is default
+make MAL_IMPL=ruby "repl^mal^step2"
+make MAL_IMPL=python "repl^mal"
+```
 
 ### Performance tests