chore: Decouple noirc_abi from frontend by introducing PrintableType

Cargo.toml

@@ -5,6 +5,7 @@ members = [
     "crates/noirc_frontend",
     "crates/noirc_errors",
     "crates/noirc_driver",
+    "crates/noirc_printable_type",
     "crates/nargo",
     "crates/nargo_cli",
     "crates/nargo_toml",
@@ -38,6 +39,7 @@ noirc_driver = { path = "crates/noirc_driver" }
 noirc_errors = { path = "crates/noirc_errors" }
 noirc_evaluator = { path = "crates/noirc_evaluator" }
 noirc_frontend = { path = "crates/noirc_frontend" }
+noirc_printable_type = { path = "crates/noirc_printable_type" }
 noir_wasm = { path = "crates/wasm" }
 cfg-if = "1.0.0"
 clap = { version = "4.3.19", features = ["derive"] }

crates/nargo/Cargo.toml

@@ -16,6 +16,7 @@ fm.workspace = true
 noirc_abi.workspace = true
 noirc_driver.workspace = true
 noirc_frontend.workspace = true
+noirc_printable_type.workspace = true
 iter-extended.workspace = true
 serde.workspace = true
 serde_json.workspace = true

crates/nargo/src/ops/foreign_calls.rs

@@ -3,7 +3,9 @@ use acvm::{
     pwg::ForeignCallWaitInfo,
 };
 use iter_extended::vecmap;
-use noirc_abi::{decode_string_value, input_parser::InputValueDisplay, AbiType};
+use noirc_printable_type::{
+    decode_string_value, decode_value, PrintableType, PrintableValueDisplay,
+};
 use regex::{Captures, Regex};
 
 use crate::errors::ForeignCallError;
@@ -93,53 +95,56 @@ impl ForeignCall {
 }
 
 fn convert_string_inputs(foreign_call_inputs: &[Vec<Value>]) -> Result<String, ForeignCallError> {
-    // Fetch the abi type from the foreign call input
+    // Fetch the PrintableType from the foreign call input
     // The remaining input values should hold what is to be printed
-    let (abi_type_as_values, input_values) =
+    let (printable_type_as_values, input_values) =
         foreign_call_inputs.split_last().ok_or(ForeignCallError::MissingForeignCallInputs)?;
-    let abi_type = fetch_abi_type(abi_type_as_values)?;
+    let printable_type = fetch_printable_type(printable_type_as_values)?;
 
     // We must use a flat map here as each value in a struct will be in a separate input value
     let mut input_values_as_fields =
         input_values.iter().flat_map(|values| vecmap(values, |value| value.to_field()));
 
-    let input_value_display =
-        InputValueDisplay::try_from_fields(&mut input_values_as_fields, abi_type)?;
+    let value = decode_value(&mut input_values_as_fields, &printable_type);
+    let input_value_display = PrintableValueDisplay::new(&value, &printable_type);
 
     Ok(input_value_display.to_string())
 }
 
 fn convert_fmt_string_inputs(
     foreign_call_inputs: &[Vec<Value>],
 ) -> Result<String, ForeignCallError> {
-    let (message_as_values, input_and_abi_values) =
+    let (message_as_values, input_and_printable_values) =
         foreign_call_inputs.split_first().ok_or(ForeignCallError::MissingForeignCallInputs)?;
 
     let message_as_fields = vecmap(message_as_values, |value| value.to_field());
     let message_as_string = decode_string_value(&message_as_fields);
 
-    let (num_values, input_and_abi_values) =
-        input_and_abi_values.split_first().ok_or(ForeignCallError::MissingForeignCallInputs)?;
+    let (num_values, input_and_printable_values) = input_and_printable_values
+        .split_first()
+        .ok_or(ForeignCallError::MissingForeignCallInputs)?;
 
     let mut output_strings = Vec::new();
     let num_values = num_values[0].to_field().to_u128() as usize;
 
-    let mut abi_types = Vec::new();
-    for abi_values in input_and_abi_values.iter().skip(input_and_abi_values.len() - num_values) {
-        let abi_type = fetch_abi_type(abi_values)?;
-        abi_types.push(abi_type);
+    let mut printable_types = Vec::new();
+    for printable_value in
+        input_and_printable_values.iter().skip(input_and_printable_values.len() - num_values)
+    {
+        let printable_type = fetch_printable_type(printable_value)?;
+        printable_types.push(printable_type);
     }
 
     for i in 0..num_values {
-        let abi_type = &abi_types[i];
-        let type_size = abi_type.field_count() as usize;
+        let printable_type = &printable_types[i];
+        let type_size = printable_type.field_count() as usize;
 
-        let mut input_values_as_fields = input_and_abi_values[i..(i + type_size)]
+        let mut input_values_as_fields = input_and_printable_values[i..(i + type_size)]
             .iter()
             .flat_map(|values| vecmap(values, |value| value.to_field()));
 
-        let input_value_display =
-            InputValueDisplay::try_from_fields(&mut input_values_as_fields, abi_type.clone())?;
+        let value = decode_value(&mut input_values_as_fields, printable_type);
+        let input_value_display = PrintableValueDisplay::new(&value, printable_type);
 
         output_strings.push(input_value_display.to_string());
     }
@@ -157,11 +162,13 @@ fn convert_fmt_string_inputs(
     Ok(formatted_str.into_owned())
 }
 
-fn fetch_abi_type(abi_type_as_values: &[Value]) -> Result<AbiType, ForeignCallError> {
-    let abi_type_as_fields = vecmap(abi_type_as_values, |value| value.to_field());
-    let abi_type_as_string = decode_string_value(&abi_type_as_fields);
-    let abi_type: AbiType = serde_json::from_str(&abi_type_as_string)
+fn fetch_printable_type(
+    printable_type_as_values: &[Value],
+) -> Result<PrintableType, ForeignCallError> {
+    let printable_type_as_fields = vecmap(printable_type_as_values, |value| value.to_field());
+    let printable_type_as_string = decode_string_value(&printable_type_as_fields);
+    let printable_type: PrintableType = serde_json::from_str(&printable_type_as_string)
         .map_err(|err| ForeignCallError::InputParserError(err.into()))?;
 
-    Ok(abi_type)
+    Ok(printable_type)
 }

crates/noirc_abi/Cargo.toml

@@ -9,6 +9,7 @@ edition.workspace = true
 [dependencies]
 acvm.workspace = true
 iter-extended.workspace = true
+noirc_frontend.workspace = true
 toml.workspace = true
 serde_json = "1.0"
 serde.workspace = true

crates/noirc_abi/src/input_parser/mod.rs

@@ -6,8 +6,8 @@ use std::collections::BTreeMap;
 use acvm::FieldElement;
 use serde::Serialize;
 
-use crate::errors::{AbiError, InputParserError};
-use crate::{decode_value, Abi, AbiType};
+use crate::errors::InputParserError;
+use crate::{Abi, AbiType};
 /// This is what all formats eventually transform into
 /// For example, a toml file will parse into TomlTypes
 /// and those TomlTypes will be mapped to Value
@@ -67,35 +67,6 @@ impl InputValue {
     }
 }
 
-/// In order to display an `InputValue` we need an `AbiType` to accurately
-/// convert the value into a human-readable format.
-pub struct InputValueDisplay {
-    input_value: InputValue,
-    abi_type: AbiType,
-}
-
-impl InputValueDisplay {
-    pub fn try_from_fields(
-        field_iterator: &mut impl Iterator<Item = FieldElement>,
-        abi_type: AbiType,
-    ) -> Result<Self, AbiError> {
-        let input_value = decode_value(field_iterator, &abi_type)?;
-        Ok(InputValueDisplay { input_value, abi_type })
-    }
-}
-
-impl std::fmt::Display for InputValueDisplay {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        // From the docs: https://doc.rust-lang.org/std/fmt/struct.Error.html
-        // This type does not support transmission of an error other than that an error
-        // occurred. Any extra information must be arranged to be transmitted through
-        // some other means.
-        let json_value = json::JsonTypes::try_from_input_value(&self.input_value, &self.abi_type)
-            .map_err(|_| std::fmt::Error)?;
-        write!(f, "{}", serde_json::to_string(&json_value).map_err(|_| std::fmt::Error)?)
-    }
-}
-
 /// The different formats that are supported when parsing
 /// the initial witness values
 #[cfg_attr(test, derive(strum_macros::EnumIter))]

crates/noirc_abi/src/lib.rs

@@ -12,6 +12,7 @@ use acvm::{
 use errors::AbiError;
 use input_parser::InputValue;
 use iter_extended::{try_btree_map, try_vecmap, vecmap};
+use noirc_frontend::{Signedness, Type, TypeBinding, TypeVariableKind, Visibility};
 use serde::{Deserialize, Serialize};
 // This is the ABI used to bridge the different TOML formats for the initial
 // witness, the partial witness generator and the interpreter.
@@ -74,6 +75,24 @@ pub enum AbiVisibility {
     Private,
 }
 
+impl From<Visibility> for AbiVisibility {
+    fn from(value: Visibility) -> Self {
+        match value {
+            Visibility::Public => AbiVisibility::Public,
+            Visibility::Private => AbiVisibility::Private,
+        }
+    }
+}
+
+impl From<&Visibility> for AbiVisibility {
+    fn from(value: &Visibility) -> Self {
+        match value {
+            Visibility::Public => AbiVisibility::Public,
+            Visibility::Private => AbiVisibility::Private,
+        }
+    }
+}
+
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "lowercase")]
 /// Represents whether the return value should compromise of unique witness indices such that no
@@ -97,6 +116,60 @@ pub enum Sign {
 }
 
 impl AbiType {
+    // TODO: Add `Context` argument for resolving fully qualified struct paths
+    pub fn from_type(typ: &Type) -> Self {
+        // Note; use strict_eq instead of partial_eq when comparing field types
+        // in this method, you most likely want to distinguish between public and private
+        match typ {
+            Type::FieldElement => Self::Field,
+            Type::Array(size, typ) => {
+                let length = size
+                    .evaluate_to_u64()
+                    .expect("Cannot have variable sized arrays as a parameter to main");
+                let typ = typ.as_ref();
+                Self::Array { length, typ: Box::new(Self::from_type(typ)) }
+            }
+            Type::Integer(sign, bit_width) => {
+                let sign = match sign {
+                    Signedness::Unsigned => Sign::Unsigned,
+                    Signedness::Signed => Sign::Signed,
+                };
+
+                Self::Integer { sign, width: *bit_width }
+            }
+            Type::TypeVariable(binding, TypeVariableKind::IntegerOrField) => {
+                match &*binding.borrow() {
+                    TypeBinding::Bound(typ) => Self::from_type(typ),
+                    TypeBinding::Unbound(_) => Self::from_type(&Type::default_int_type()),
+                }
+            }
+            Type::Bool => Self::Boolean,
+            Type::String(size) => {
+                let size = size
+                    .evaluate_to_u64()
+                    .expect("Cannot have variable sized strings as a parameter to main");
+                Self::String { length: size }
+            }
+            Type::FmtString(_, _) => unreachable!("format strings cannot be used in the abi"),
+            Type::Error => unreachable!(),
+            Type::Unit => unreachable!(),
+            Type::Constant(_) => unreachable!(),
+            Type::Struct(def, ref args) => {
+                let struct_type = def.borrow();
+                let fields = struct_type.get_fields(args);
+                let fields = vecmap(fields, |(name, typ)| (name, Self::from_type(&typ)));
+                Self::Struct { fields, name: struct_type.name.to_string() }
+            }
+            Type::Tuple(_) => todo!("as_abi_type not yet implemented for tuple types"),
+            Type::TypeVariable(_, _) => unreachable!(),
+            Type::NamedGeneric(..) => unreachable!(),
+            Type::Forall(..) => unreachable!(),
+            Type::Function(_, _, _) => unreachable!(),
+            Type::MutableReference(_) => unreachable!("&mut cannot be used in the abi"),
+            Type::NotConstant => unreachable!(),
+        }
+    }
+
     /// Returns the number of field elements required to represent the type once encoded.
     pub fn field_count(&self) -> u32 {
         match self {
@@ -390,7 +463,7 @@ fn decode_value(
     Ok(value)
 }
 
-pub fn decode_string_value(field_elements: &[FieldElement]) -> String {
+fn decode_string_value(field_elements: &[FieldElement]) -> String {
     let string_as_slice = vecmap(field_elements, |e| {
         let mut field_as_bytes = e.to_be_bytes();
         let char_byte = field_as_bytes.pop().unwrap(); // A character in a string is represented by a u8, thus we just want the last byte of the element

crates/noirc_driver/src/lib.rs

@@ -135,7 +135,7 @@ pub fn compute_function_abi(
 
     let (parameters, return_type) = func_meta.into_function_signature();
     let parameters = into_abi_params(parameters, &context.def_interner);
-    let return_type = return_type.map(|typ| typ.as_abi_type());
+    let return_type = return_type.map(|typ| AbiType::from_type(&typ));
     Some((parameters, return_type))
 }
 

crates/noirc_evaluator/src/ssa/abi_gen/mod.rs

@@ -2,7 +2,7 @@ use std::collections::BTreeMap;
 
 use acvm::acir::native_types::Witness;
 use iter_extended::{btree_map, vecmap};
-use noirc_abi::{Abi, AbiParameter};
+use noirc_abi::{Abi, AbiParameter, AbiType};
 use noirc_frontend::{
     hir_def::{
         function::{FunctionSignature, Param},
@@ -27,7 +27,7 @@ pub fn into_abi_params(params: Vec<Param>, interner: &NodeInterner) -> Vec<AbiPa
         let param_name = get_param_name(&pattern, interner)
             .expect("Abi for tuple and struct parameters is unimplemented")
             .to_owned();
-        let as_abi = typ.as_abi_type();
+        let as_abi = AbiType::from_type(&typ);
         AbiParameter { name: param_name, typ: as_abi, visibility: vis.into() }
     })
 }
@@ -42,7 +42,7 @@ pub(crate) fn gen_abi(
 ) -> Abi {
     let (parameters, return_type) = func_sig;
     let parameters = into_abi_params(parameters, interner);
-    let return_type = return_type.map(|typ| typ.as_abi_type());
+    let return_type = return_type.map(|typ| AbiType::from_type(&typ));
     let param_witnesses = param_witnesses_from_abi_param(&parameters, input_witnesses);
     Abi { parameters, return_type, param_witnesses, return_witnesses }
 }

crates/noirc_frontend/Cargo.toml

@@ -8,15 +8,14 @@ edition.workspace = true
 
 [dependencies]
 acvm.workspace = true
-noirc_abi.workspace = true
 noirc_errors.workspace = true
+noirc_printable_type.workspace = true
 fm.workspace = true
 arena.workspace = true
 iter-extended.workspace = true
 chumsky.workspace = true
 thiserror.workspace = true
 smol_str.workspace = true
-serde.workspace = true
 serde_json.workspace = true
 rustc-hash = "1.1.0"
 small-ord-set = "0.1.3"

crates/noirc_frontend/src/ast/expression.rs

@@ -382,8 +382,7 @@ pub enum FunctionReturnType {
 
 /// Describes the types of smart contract functions that are allowed.
 /// - All Noir programs in the non-contract context can be seen as `Secret`.
-#[derive(serde::Serialize, serde::Deserialize, Debug, Copy, Clone, PartialEq, Eq)]
-#[serde(rename_all = "snake_case")]
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub enum ContractFunctionType {
     /// This function will be executed in a private
     /// context.