Merge #143: refactors to prepare for the new rust-simplicity version

760c51c move ProgNode into compile.rs as a private type (Andrew Poelstra)
142e63c move builtins from crate root to private module in compile (Andrew Poelstra)
cbf7ce6 rename src/compile.rs to src/compile/mod.rs (Andrew Poelstra)
7f1d12a move type checking from lib.rs into compile.rs (Andrew Poelstra)
5fce3d4 replace Construct with Commit in CompiledProgram (Andrew Poelstra)
6d864bb named: add finalize_types function (Andrew Poelstra)
7150f0e named: replace ad-hoc ConstructNode/CommitNode/WitnessNode with generic ones (Andrew Poelstra)
60f65b4 remove Default impl from CompiledProgram (Andrew Poelstra)

Pull request description:

  Since BlockstreamResearch/rust-simplicity#305 we are not allowed to have type inference contexts (and therefore `ConstructNode`s) that escape the lexical scope that defines them.
  
  We currently use `ConstructNode` inside `ProgramNode`. This PR changes this to `CommitNode`, which is more correct, as well as being necessary to avoid exposing bad `GhostCell` ergonomics to users of this library.


ACKs for top commit:
  delta1:
    ACK 760c51c 


Tree-SHA512: 15d99c72c262ec88e873fb4e3cc6025c1ecf4ec848b22f4b45fb8e5f40c98d5aea3421f1fbd0f3d68f83fc04797495e1665d71d4d1b5b11b4b94c5c088df451b

Author: apoelstra

src/builtins.rs renamed to src/compile/builtins.rs

@@ -2,7 +2,8 @@ use std::num::NonZeroUsize;
 
 use simplicity::node::CoreConstructible;
 
-use crate::{named::CoreExt, ProgNode};
+use super::ProgNode;
+use crate::named::CoreExt;
 
 /// Fold an array of size `size` elements using function `f`.
 ///

src/compile.rs renamed to src/compile/mod.rs

@@ -1,28 +1,32 @@
 //! Compile the parsed ast into a simplicity program
 
+mod builtins;
+
 use std::sync::Arc;
 
 use either::Either;
 use simplicity::jet::Elements;
 use simplicity::node::{CoreConstructible as _, JetConstructible as _};
 use simplicity::{Cmr, FailEntropy};
 
+use self::builtins::array_fold;
 use crate::array::{BTreeSlice, Partition};
 use crate::ast::{
     Call, CallName, Expression, ExpressionInner, Match, Program, SingleExpression,
     SingleExpressionInner, Statement,
 };
-use crate::builtins::array_fold;
 use crate::debug::CallTracker;
 use crate::error::{Error, RichError, Span, WithSpan};
-use crate::named::{CoreExt, PairBuilder};
+use crate::named::{self, CoreExt, PairBuilder};
 use crate::num::{NonZeroPow2Usize, Pow2Usize};
 use crate::pattern::{BasePattern, Pattern};
 use crate::str::WitnessName;
 use crate::types::{StructuralType, TypeDeconstructible};
 use crate::value::StructuralValue;
 use crate::witness::Arguments;
-use crate::{ProgNode, Value};
+use crate::Value;
+
+type ProgNode = Arc<named::ConstructNode<Elements>>;
 
 /// Each SimplicityHL expression expects an _input value_.
 /// A SimplicityHL expression is translated into a Simplicity expression
@@ -258,13 +262,18 @@ impl Program {
         &self,
         arguments: Arguments,
         include_debug_symbols: bool,
-    ) -> Result<ProgNode, RichError> {
+    ) -> Result<Arc<named::CommitNode<Elements>>, RichError> {
         let mut scope = Scope::new(
             Arc::clone(self.call_tracker()),
             arguments,
             include_debug_symbols,
         );
-        self.main().compile(&mut scope).map(PairBuilder::build)
+
+        let main = self.main();
+        let construct = main.compile(&mut scope).map(PairBuilder::build)?;
+        // SimplicityHL types should be correct by construction. If not, assign the
+        // whole main function as the span for them, which is as sensible as anything.
+        named::finalize_types(&construct).with_span(main)
     }
 }
 

src/lib.rs

@@ -1,10 +1,7 @@
 //! Library for parsing and compiling SimplicityHL
 
-pub type ProgNode = Arc<named::ConstructNode>;
-
 pub mod array;
 pub mod ast;
-pub mod builtins;
 pub mod compile;
 pub mod debug;
 pub mod dummy_env;
@@ -81,12 +78,15 @@ impl TemplateProgram {
         arguments
             .is_consistent(self.simfony.parameters())
             .map_err(|error| error.to_string())?;
+
+        let commit = self
+            .simfony
+            .compile(arguments, include_debug_symbols)
+            .with_file(Arc::clone(&self.file))?;
+
         Ok(CompiledProgram {
             debug_symbols: self.simfony.debug_symbols(self.file.as_ref()),
-            simplicity: self
-                .simfony
-                .compile(arguments, include_debug_symbols)
-                .with_file(Arc::clone(&self.file))?,
+            simplicity: commit,
             witness_types: self.simfony.witness_types().shallow_clone(),
         })
     }
@@ -95,22 +95,11 @@ impl TemplateProgram {
 /// A SimplicityHL program, compiled to Simplicity.
 #[derive(Clone, Debug)]
 pub struct CompiledProgram {
-    simplicity: ProgNode,
+    simplicity: Arc<named::CommitNode<Elements>>,
     witness_types: WitnessTypes,
     debug_symbols: DebugSymbols,
 }
 
-impl Default for CompiledProgram {
-    fn default() -> Self {
-        use simplicity::node::CoreConstructible;
-        Self {
-            simplicity: ProgNode::unit(&simplicity::types::Context::new()),
-            witness_types: WitnessTypes::default(),
-            debug_symbols: DebugSymbols::default(),
-        }
-    }
-}
-
 impl CompiledProgram {
     /// Parse and compile a SimplicityHL program from the given string.
     ///
@@ -134,8 +123,7 @@ impl CompiledProgram {
 
     /// Access the Simplicity target code, without witness data.
     pub fn commit(&self) -> Arc<CommitNode<Elements>> {
-        named::to_commit_node(&self.simplicity)
-            .expect("Compiled SimplicityHL program has type 1 -> 1")
+        named::forget_names(&self.simplicity)
     }
 
     /// Satisfy the SimplicityHL program with the given `witness_values`.
@@ -163,13 +151,13 @@ impl CompiledProgram {
         witness_values
             .is_consistent(&self.witness_types)
             .map_err(|e| e.to_string())?;
-        let simplicity_witness = named::to_witness_node(&self.simplicity, witness_values);
-        let simplicity_redeem = match env {
-            Some(env) => simplicity_witness.finalize_pruned(env),
-            None => simplicity_witness.finalize_unpruned(),
-        };
+
+        let mut simplicity_redeem = named::populate_witnesses(&self.simplicity, witness_values)?;
+        if let Some(env) = env {
+            simplicity_redeem = simplicity_redeem.prune(env).map_err(|e| e.to_string())?;
+        }
         Ok(SatisfiedProgram {
-            simplicity: simplicity_redeem.map_err(|e| e.to_string())?,
+            simplicity: simplicity_redeem,
             debug_symbols: self.debug_symbols.clone(),
         })
     }