feat: implement Chapter 7

test/manual-suite.spt

@@ -161,3 +161,42 @@ test sec6_2_dnf_exercise_ex [[
   p = q
 ]] run better-dnf to Or(And(Not(Atom("p")),Not(Atom("q"))),
                         And(Atom("q"),Atom("p")))
+
+/** md
+### Chapter 7
+
+The content and style of chapter 7 are similar to chapter 6. Again, there is a
+`trans/chap7.str` Stratego file defining several of the rules used in the examples
+from the chapter. As before, the examples with a different signature are recast
+into the SPL signature. Specifically, `Z` becomes `False`, `S(x)` becomes
+`Impl(True(), x)`, and `P` becomes `Or`.
+**/
+
+test sec7_2_b_ex [[
+  (1 -> 0) | 0
+]] run B to Or(False(), Impl(True(), False()))
+
+test sec7_2_b_a_ex [[
+  (1 -> 0) | 0
+]] run BthenA to Impl(True(), False())
+
+test sec7_2_b_b_fails [[
+  (1 -> 0) | 0
+]] run Btwice fails
+
+test sec7_2_local_choice_fails [[
+  (1 -> 0) | 0
+]] run maybeB-id-thenB fails
+
+test sec7_2_seq_no_dist_over_choice_ex [[
+  (1 -> 0) | 0
+]] run maybeBtwice-idthenB to Or(False(), Impl(True(), False()))
+
+test sec7_3_repeat_small_ex [[
+  (1 -> 0) | 0
+]] run repeatmaybeAB to Impl(True(), False())
+
+test sec7_3_repeat_big_ex [[
+  (1 -> (1 -> (1 -> (1 -> 0)))) | 0
+]] run repeatmaybeAB to Impl(True(), Impl(True(), Impl(True(),
+                                                       Impl(True(), False()))))

trans/chap7.str

@@ -0,0 +1,15 @@
+module chap7
+imports libstrategolib signatures/-
+
+rules
+
+  A : Or(False(), x) -> x
+  B : Or(Impl(True(),x), y) -> Or(x, Impl(True(), y))
+
+strategies
+
+  BthenA = B; A
+  Btwice = B; B
+  maybeB-id-thenB = (B <+ id); B
+  maybeBtwice-idthenB = Btwice <+ (id; B)
+  repeatmaybeAB = repeat(A <+ B)

trans/spoofax_propositional_language.str

@@ -14,6 +14,7 @@ imports
   prop-eval2
   prop-desugar
   chap6
+  chap7
 
 rules // Debugging