track isabelle binary in Makefile

Author: Edoardo Putti

Makefile

@@ -12,6 +12,14 @@
 
 # Set this to the directory containing the Isabelle2025-2 binary
 ISABELLE_HOME?=/Applications/Isabelle2025-2.app/bin
+
+ISABELLE_BIN := $(ISABELLE_HOME)/isabelle
+
+ifeq ($(wildcard $(ISABELLE_BIN)),)
+$(error Isabelle binary not found at $(ISABELLE_BIN). \
+Set ISABELLE_HOME correctly, e.g. make ISABELLE_HOME=/path/to/Isabelle/bin)
+endif
+
 # Set this to your home directory
 USER_HOME?=$(HOME)
 # Set this to where you maintain, or want to maintain, AFP dependencies
@@ -40,10 +48,10 @@ ISABELLE_FLAGS += $(ISABELLE_REMOTE)
 ISABELLE_JEDIT_FLAGS += $(ISABELLE_REMOTE)
 
 jedit: register-afp-components
-	$(ISABELLE_HOME)/isabelle jedit $(ISABELLE_JEDIT_FLAGS) -l HOL -d . ./AutoCorrode.thy  &
+	$(ISABELLE_BIN) jedit $(ISABELLE_JEDIT_FLAGS) -l HOL -d . ./AutoCorrode.thy  &
 
 register-afp-components:
-	$(ISABELLE_HOME)/isabelle components -u $(AFP_COMPONENT_BASE)/Word_Lib
+	$(ISABELLE_BIN) components -u $(AFP_COMPONENT_BASE)/Word_Lib
 
 build: register-afp-components
-	$(ISABELLE_HOME)/isabelle build $(ISABELLE_FLAGS) -d . AutoCorrode
+	$(ISABELLE_BIN) build $(ISABELLE_FLAGS) -d . AutoCorrode