staging commit with const input syntax and constants processing

asg/src/const_value.rs

@@ -91,6 +91,16 @@ pub enum GroupValue {
     Tuple(GroupCoordinate, GroupCoordinate),
 }
 
+impl From<leo_ast::GroupValue> for GroupValue {
+    fn from(other: leo_ast::GroupValue) -> Self {
+        use leo_ast::GroupValue::*;
+        match other {
+            Single(value, _) => GroupValue::Single(value),
+            Tuple(value) => GroupValue::Tuple(GroupCoordinate::from(&value.x), GroupCoordinate::from(&value.y)),
+        }
+    }
+}
+
 #[derive(Clone, Debug, PartialEq)]
 pub enum ConstValue {
     Int(ConstInt),

ast/src/input/input.rs

@@ -94,9 +94,10 @@ impl Input {
         Ok(())
     }
 
-    /// Returns the main function input value with the given `name`
+    /// Returns the main function input value with the given `name`, second parameter
+    /// is a boolean indicating whether parameter is const.
     #[allow(clippy::ptr_arg)]
-    pub fn get(&self, name: &String) -> Option<Option<InputValue>> {
+    pub fn get(&self, name: &String) -> Option<(Option<InputValue>, bool)> {
         self.program_input.get(name)
     }
 

ast/src/input/program_input/main_input.rs

@@ -22,6 +22,7 @@ use indexmap::IndexMap;
 #[derive(Clone, PartialEq, Eq, Default)]
 pub struct MainInput {
     input: IndexMap<String, Option<InputValue>>,
+    constants: IndexMap<String, Option<InputValue>>,
 }
 
 #[allow(clippy::len_without_is_empty)]
@@ -34,16 +35,21 @@ impl MainInput {
     /// Called during constraint synthesis to provide private input variables.
     pub fn empty(&self) -> Self {
         let mut input = self.input.clone();
+        let mut constants = self.constants.clone();
 
         input.iter_mut().for_each(|(_name, value)| {
             *value = None;
         });
 
-        Self { input }
+        constants.iter_mut().for_each(|(_name, value)| {
+            *value = None;
+        });
+
+        Self { input, constants }
     }
 
     pub fn len(&self) -> usize {
-        self.input.len()
+        self.input.len() + self.constants.len()
     }
 
     pub fn insert(&mut self, key: String, value: Option<InputValue>) {
@@ -54,16 +60,27 @@ impl MainInput {
     pub fn parse(&mut self, definitions: Vec<Definition>) -> Result<(), InputParserError> {
         for definition in definitions {
             let name = definition.parameter.variable.value;
+            let is_const = definition.const_.is_some();
             let value = InputValue::from_expression(definition.parameter.type_, definition.expression)?;
 
-            self.insert(name, Some(value));
+            if is_const {
+                self.constants.insert(name, Some(value));
+            } else {
+                self.input.insert(name, Some(value));
+            }
         }
 
         Ok(())
     }
 
-    /// Returns an `Option` of the main function input at `name`
-    pub fn get(&self, name: &str) -> Option<Option<InputValue>> {
-        self.input.get(name).cloned()
+    /// Returns an `Option` of the main function input at `name`. As a second
+    /// value in a tuple returns flag whether input is defined as a constant in input file.
+    pub fn get(&self, name: &str) -> Option<(Option<InputValue>, bool)> {
+        // As we check key presence in IndexMap unwraps below can be considered secure.
+        match (self.input.contains_key(name), self.constants.contains_key(name)) {
+            (true, _) => Some((self.input.get(name).cloned().unwrap(), false)),
+            (_, true) => Some((self.constants.get(name).cloned().unwrap(), true)),
+            (_, _) => None,
+        }
     }
 }

ast/src/input/program_input/program_input.rs

@@ -66,7 +66,7 @@ impl ProgramInput {
 
     /// Returns the main function input value with the given `name`
     #[allow(clippy::ptr_arg)]
-    pub fn get(&self, name: &String) -> Option<Option<InputValue>> {
+    pub fn get(&self, name: &String) -> Option<(Option<InputValue>, bool)> {
         self.main.get(name)
     }
 

ast/src/types/integer_type.rs

@@ -23,7 +23,7 @@ use leo_input::types::{
 use serde::{Deserialize, Serialize};
 use std::fmt;
 
-/// Explicit integer type
+/// Explicit integer type.
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
 pub enum IntegerType {
     U8,

compiler/src/compiler.rs

@@ -172,7 +172,6 @@ impl<'a, F: PrimeField, G: GroupType<F>> Compiler<'a, F, G> {
 
             e
         })?;
-
         self.program_input.parse_input(input_syntax_tree).map_err(|mut e| {
             e.set_path(
                 input_path.to_str().unwrap_or_default(),

compiler/src/expression/arithmetic/bit_not.rs

@@ -25,8 +25,5 @@ pub fn evaluate_bit_not<'a, F: PrimeField, G: GroupType<F>>(
     value: ConstrainedValue<'a, F, G>,
     span: &Span,
 ) -> Result<ConstrainedValue<'a, F, G>, IntegerError> {
-    match value {
-        // ConstrainedValue::Integer(i) => Ok(ConstrainedValue::Integer(i.not())),
-        value => Err(IntegerError::cannot_evaluate(format!("~{}", value), span)),
-    }
+    Err(IntegerError::cannot_evaluate(format!("~{}", value), span))
 }

compiler/src/function/input/main_function_input.rs

@@ -26,15 +26,19 @@ use crate::{
         group::input::group_from_input,
         ConstrainedValue,
     },
+    FieldType,
     GroupType,
     Integer,
 };
 
-use leo_asg::Type;
-use leo_ast::{InputValue, Span};
+use leo_asg::{ConstInt, Type};
+use leo_ast::{InputValue, IntegerType, Span};
 use snarkvm_fields::PrimeField;
+use snarkvm_gadgets::traits::utilities::boolean::Boolean;
 use snarkvm_r1cs::ConstraintSystem;
 
+// use crate::value::{Address, ConstrainedValue, Integer};
+
 impl<'a, F: PrimeField, G: GroupType<F>> ConstrainedProgram<'a, F, G> {
     pub fn allocate_main_function_input<CS: ConstraintSystem<F>>(
         &mut self,
@@ -62,3 +66,48 @@ impl<'a, F: PrimeField, G: GroupType<F>> ConstrainedProgram<'a, F, G> {
         }
     }
 }
+
+/// Process constant inputs and return ConstrainedValue with constant value in it.
+impl<'a, F: PrimeField, G: GroupType<F>> ConstrainedProgram<'a, F, G> {
+    pub fn parse_constant_main_function_input<CS: ConstraintSystem<F>>(
+        &mut self,
+        // TODO: remove unnecessary arguments
+        _cs: &mut CS,
+        _type_: &Type,
+        name: &str,
+        input_option: Option<InputValue>,
+        span: &Span,
+    ) -> Result<ConstrainedValue<'a, F, G>, FunctionError> {
+        let value = input_option.unwrap();
+
+        Ok(match value {
+            InputValue::Address(value) => ConstrainedValue::Address(Address::constant(value, span)?),
+            InputValue::Boolean(value) => ConstrainedValue::Boolean(Boolean::constant(value)),
+            InputValue::Field(value) => ConstrainedValue::Field(FieldType::constant(value, span)?),
+            InputValue::Group(value) => ConstrainedValue::Group(G::constant(&value.into(), span)?),
+            InputValue::Integer(integer_type, value) => {
+                let integer = IntegerType::from(integer_type);
+                let const_int = match integer {
+                    IntegerType::U8 => ConstInt::U8(value.parse::<u8>().unwrap()),
+                    IntegerType::U16 => ConstInt::U16(value.parse::<u16>().unwrap()),
+                    IntegerType::U32 => ConstInt::U32(value.parse::<u32>().unwrap()),
+                    IntegerType::U64 => ConstInt::U64(value.parse::<u64>().unwrap()),
+                    IntegerType::U128 => ConstInt::U128(value.parse::<u128>().unwrap()),
+
+                    IntegerType::I8 => ConstInt::I8(value.parse::<i8>().unwrap()),
+                    IntegerType::I16 => ConstInt::I16(value.parse::<i16>().unwrap()),
+                    IntegerType::I32 => ConstInt::I32(value.parse::<i32>().unwrap()),
+                    IntegerType::I64 => ConstInt::I64(value.parse::<i64>().unwrap()),
+                    IntegerType::I128 => ConstInt::I128(value.parse::<i128>().unwrap()),
+                };
+
+                ConstrainedValue::Integer(Integer::new(&const_int))
+            }
+            // TODO: array and tuple values.
+            // InputValue::Array(Vec<InputValue>) => ,
+            // InputValue::Tuple(Vec<InputValue>),
+            // TODO: rework this error to something better fitting into context.
+            _ => return Err(FunctionError::input_not_found(name.to_string(), span)),
+        })
+    }
+}

compiler/src/function/main_function.rs

@@ -61,16 +61,28 @@ impl<'a, F: PrimeField, G: GroupType<F>> ConstrainedProgram<'a, F, G> {
             {
                 let input_variable = input_variable.get().borrow();
                 let name = input_variable.name.name.clone();
-                let input_option = input.get(&name).ok_or_else(|| {
+
+                let (input_option, is_const) = input.get(&name).ok_or_else(|| {
                     FunctionError::input_not_found(name.clone(), &function.span.clone().unwrap_or_default())
                 })?;
-                let input_value = self.allocate_main_function_input(
-                    cs,
-                    &input_variable.type_.clone(),
-                    &name,
-                    input_option,
-                    &function.span.clone().unwrap_or_default(),
-                )?;
+
+                let input_value = if is_const {
+                    self.parse_constant_main_function_input(
+                        cs,
+                        &input_variable.type_.clone(),
+                        &name,
+                        input_option,
+                        &function.span.clone().unwrap_or_default(),
+                    )?
+                } else {
+                    self.allocate_main_function_input(
+                        cs,
+                        &input_variable.type_.clone(),
+                        &name,
+                        input_option,
+                        &function.span.clone().unwrap_or_default(),
+                    )?
+                };
 
                 // Store a new variable for every allocated main function input
                 self.store(input_variable.id, input_value);

input/src/definitions/const_.rs

@@ -0,0 +1,27 @@
+// Copyright (C) 2019-2021 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::ast::Rule;
+
+use pest::Span;
+use pest_ast::FromPest;
+
+#[derive(Clone, Debug, FromPest, PartialEq)]
+#[pest_ast(rule(Rule::const_))]
+pub struct Const<'ast> {
+    #[pest_ast(outer())]
+    pub span: Span<'ast>,
+}

input/src/definitions/definition.rs

@@ -14,6 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
 
+use super::Const;
 use crate::{ast::Rule, common::LineEnd, expressions::Expression, parameters::Parameter};
 
 use pest::Span;
@@ -22,9 +23,17 @@ use pest_ast::FromPest;
 #[derive(Clone, Debug, FromPest, PartialEq)]
 #[pest_ast(rule(Rule::definition))]
 pub struct Definition<'ast> {
+    pub const_: Option<Const<'ast>>,
     pub parameter: Parameter<'ast>,
     pub expression: Expression<'ast>,
     pub line_end: LineEnd,
     #[pest_ast(outer())]
     pub span: Span<'ast>,
 }
+
+impl<'ast> Definition<'ast> {
+    /// Check whether `const` keyword is placed before definition.
+    pub fn is_const(&self) -> bool {
+        self.const_.is_some()
+    }
+}

input/src/definitions/mod.rs

@@ -16,3 +16,6 @@
 
 pub mod definition;
 pub use definition::*;
+
+pub mod const_;
+pub use const_::*;

input/src/leo-input.pest

@@ -218,8 +218,11 @@ header = { main | record | registers | state_leaf | state | identifier }
 
 /// Definitions
 
+// Declared in definition/const_modifier.rs
+const_ = { "const" }
+
 // Declared in definition/definition.rs
-definition = { parameter ~ "=" ~ expression ~ LINE_END }
+definition = { const_? ~ parameter ~ "=" ~ expression ~ LINE_END }
 
 /// Table