#171 @call : initial design considerations

docs/@call.md

@@ -1,9 +1,36 @@
 
 # @call
+       
+## Naming: `@call` vs `@calls`
+
+TODO
 
 ## Do we allow both `@call` and `@depends_on` on the same level?
+                          
+```shell
+@goal a
+@call b
+@depends_on c
+```
+
+We could but the execution model would be this (`@depends_on` go first):
+```shell
+@goal a
+@depends_on c
+"$MAKESURE" b
+```
+
+Answer: No, should result in error in the first iteration.
+
+## Do we allow both `@call` and non-empty goal body?
+
+```shell
+@goal a
+@call b
+  echo 'a body'
+```
 
-No, should result in error
+Should be relatively easy.  
 
 ## Do we allow `@call goal_name @args 'arg'`?
 
@@ -29,6 +56,26 @@ Maybe, but let's do the easiest for the first iteration
 
 In the first iteration let's not generate a subtree. 
 
+## `@call` operational semantics
+
+Let's implement the simplest strategy of passthrough to `./makesure` invocation
+
+```shell
+@goal a
+@call b
+```
+
+desugars to
+
+```shell
+@goal a
+"$MAKESURE" [--define ...] b
+```
+
+Do we need `--file 'path/to/Makesurefile'`?
+
+No. Even if we run `./makesure path/to/Makesurefile` path resolution is relative to the `Makesurefile` location, so internal makesure invocation now doesn't need explicit Makesurefile reference. But let's add a test for this case.
+
 ## the `@define` inheritance
 
 Since we implement this in terms of running the external `./makesure` we need to repeat the variables passed via `-D`.
@@ -62,10 +109,10 @@ desugars to
   echo "a2: $A"
 
 @define b
-  "$MAKESURE" -D A="$A" a1
-  "$MAKESURE" -D A="$A" a2
+  "$MAKESURE" --define A="$A" a1
+  "$MAKESURE" --define A="$A" a2
 
 @define c
-  "$MAKESURE" -D A="$A" a1
-  "$MAKESURE" -D A="$A" a2
+  "$MAKESURE" --define A="$A" a1
+  "$MAKESURE" --define A="$A" a2
 ```