1 files changed, 35 insertions, 0 deletions
diff --git a/lib/coq/Sail2_string.v b/lib/coq/Sail2_string.v
new file mode 100644
index 00000000..9ca9cb67
--- /dev/null
+++ b/lib/coq/Sail2_string.v
@@ -0,0 +1,35 @@
+Require Import Sail2_values.
+
+Definition string_sub (s : string) (start : Z) (len : Z) : string :=
+  String.substring (Z.to_nat start) (Z.to_nat len) s.
+
+Definition string_startswith s expected :=
+  let prefix := String.substring 0 (String.length expected) s in
+  generic_eq prefix expected.
+
+Definition string_drop s (n : {n : Z & ArithFact (n >= 0)}) :=
+  let n := Z.to_nat (projT1 n) in
+  String.substring n (String.length s - n) s.
+
+Definition string_length s : {n : Z & ArithFact (n >= 0)} :=
+ build_ex (Z.of_nat (String.length s)).
+
+Definition string_append := String.append.
+
+(* TODO: maybe_int_of_prefix, maybe_int_of_string *)
+
+Fixpoint n_leading_spaces (s:string) : nat :=
+  match s with
+  | EmptyString => 0
+  | String " " t => S (n_leading_spaces t)
+  | _ => 0
+  end.
+
+Definition opt_spc_matches_prefix s : option (unit * {n : Z & ArithFact (n >= 0)}) :=
+  Some (tt, build_ex (Z.of_nat (n_leading_spaces s))).
+
+Definition spc_matches_prefix s : option (unit * {n : Z & ArithFact (n >= 0)}) :=
+  match n_leading_spaces s with
+  | O => None
+  | S n => Some (tt, build_ex (Z.of_nat (S n)))
+  end.
+\ No newline at end of file