#171 @call : initial design considerations

docs/@call.md

@@ -0,0 +1,71 @@
+
+# @call
+
+## Do we allow both `@call` and `@depends_on` on the same level?
+
+No, should result in error
+
+## Do we allow `@call goal_name @args 'arg'`?
+
+Let's allow. The goal will be instantiated the same way as for `@depends_on`
+
+What about
+
+```shell
+@goal pg1 @params P1 P2
+ echo "pg1: $P1 $P2"
+
+@goal pg @params A
+@call pg1 @args A "A=$A"
+```
+
+Answer: interpolation rules should apply the same as for `@depends_on`, i.e. all works as expected.
+
+## Can we implement it more efficient than just running more makesure processes?
+
+Maybe, but let's do the easiest for the first iteration
+
+## How do we output the dependency tree (`-d`,`--resolved`)
+
+In the first iteration let's not generate a subtree. 
+
+## the `@define` inheritance
+
+Since we implement this in terms of running the external `./makesure` we need to repeat the variables passed via `-D`.
+
+```shell
+@define A 'a'
+
+@define a1
+  echo "a1: $A"
+
+@define a2
+  echo "a2: $A"
+
+@define b
+@call a1 
+@call a2 
+
+@define c
+@call a1 a2 
+```
+
+desugars to 
+
+```shell
+@define A 'a'
+
+@define a1
+  echo "a1: $A"
+
+@define a2
+  echo "a2: $A"
+
+@define b
+  "$MAKESURE" -D A="$A" a1
+  "$MAKESURE" -D A="$A" a2
+
+@define c
+  "$MAKESURE" -D A="$A" a1
+  "$MAKESURE" -D A="$A" a2
+```