also fix imports

exercises/compatibility.v

-From solutions Require Export sem_typed sem_operators.
+From exercises Require Export sem_typed sem_operators.
 
 (** * Compatibility lemmas *)
 (** We prove that the logical relations, i.e., the semantic typing judgment,

exercises/demo.v

-From solutions Require Import language.
+From exercises Require Import language.
 From iris.base_logic.lib Require Import invariants.
 From iris.heap_lang Require Import adequacy.
 

exercises/fundamental.v

-From solutions Require Export typed compatibility interp.
+From exercises Require Export typed compatibility interp.
 
 (** * The fundamental theorem of logical relations *)
 (** The fundamental theorem of logical relations says that any syntactically

exercises/interp.v

-From solutions Require Export sem_typed sem_type_formers types.
+From exercises Require Export sem_typed sem_type_formers types.
 
 (** * Interpretation of syntactic types *)
 (** We use semantic type formers to define the interpretation [⟦ τ ⟧ : sem_ty]

exercises/parametricity.v

-From solutions Require Export safety.
+From exercises Require Export safety.
 
 (** * Parametricity *)
 Section parametricity.

exercises/polymorphism.v

-From solutions Require Export language.
+From exercises Require Export language.
 
 (** * Polymorphism and existential types in HeapLang *)
 (** In order to define a type system for HeapLang (in the file [typed.v]), we

exercises/safety.v

 From iris.heap_lang Require Export adequacy.
-From solutions Require Export fundamental.
+From exercises Require Export fundamental.
 
 (** * Semantic and syntactic type safety *)
 (** We prove *semantic type safety*, which says that any _closed_ expression

exercises/sem_operators.v

-From solutions Require Export sem_typed.
+From exercises Require Export sem_typed.
 
 (** Semantic operator typing *)
 Class SemTyUnboxed `{!heapG Σ} (A : sem_ty Σ) :=

exercises/sem_type_formers.v

-From solutions Require Export sem_types.
+From exercises Require Export sem_types.
 
 (** * Semantic type formers *)
 (** For all of the type formers in the syntactic type system, we now define

exercises/sem_typed.v

-From solutions Require Export sem_type_formers.
+From exercises Require Export sem_type_formers.
 
 (** * The semantic typing judgment *)
 

exercises/sem_types.v

-From solutions Require Export polymorphism.
+From exercises Require Export polymorphism.
 From iris.heap_lang Require Export proofmode.
 From iris.base_logic.lib Require Export invariants.
 

exercises/typed.v

-From solutions Require Export types polymorphism.
+From exercises Require Export types polymorphism.
 
 (** * Syntactic typing for HeapLang *)
 (** In this file, we define a syntactic type system for HeapLang. We do this

exercises/types.v

-From solutions Require Export language.
+From exercises Require Export language.
 
 (** * Syntactic types for HeapLang *)
 (** The inductive type [ty] defines the syntactic types for HeapLang. We make

exercises/unsafe.v

-From solutions Require Export sem_typed.
-From solutions Require Import symbol_ghost two_state_ghost.
+From exercises Require Export sem_typed.
+From exercises Require Import symbol_ghost two_state_ghost.
 
 Section unsafe.
   Context `{!heapG Σ}.

mk-exercises.sh

@@ -7,6 +7,7 @@ REMOVEPRF_RE='s/\(\*\s*REMOVE\s*\*\)\s*Proof.\s*.*?\s*Qed\.\R/Proof. (* FILL IN
 REMOVE_RE='s/\(\*\s*REMOVE\s*\*\)\s*(.*?)\s*:=.*?\.\R/\1. (* FILL IN HERE *) Admitted.\n/gms'
 STRONGHIDE_RE='s/\(\*\s*STRONGHIDE\s*\*\)\s*(.*?)\(\*\s*ENDSTRONGHIDE\s*\*\)\R?//gms'
 HIDE_RE='s/\(\*\s*HIDE\s*\*\)\s*(.*?)\(\*\s*ENDHIDE\s*\*\)/Definition hole := remove_this_line.\n(* ANSWER THE QUESTION AND REMOVE THE LINE ABOVE *)/gms'
+IMPORT_RE='s/^From solutions/From exercises/gms'
 
 # run replacement on all source files
 mkdir -p exercises
@@ -16,5 +17,6 @@ for FILE in solutions/*.v; do
       | $REPLACE "$REMOVEPRF_RE" \
       | $REPLACE "$REMOVE_RE" \
       | $REPLACE "$STRONGHIDE_RE" \
-      | $REPLACE "$HIDE_RE" > "$DST"
+      | $REPLACE "$HIDE_RE" \
+      | $REPLACE "$IMPORT_RE" > "$DST"
 done