add private field to params. WIP

examples/factorization.code

@@ -1,4 +1,4 @@
 // a and b are factorization of c
-def main(c):
+def main(c, private a, private b):
   c == a * b
   return 1

examples/private.code

@@ -0,0 +1,13 @@
+// only using sub, no need to flatten
+def main(x, private y):
+  a = 5
+  b = 7
+  c = if a == b then 4 else 3 fi
+  c == 3
+  d = if a == 5 then 1 else 2 fi
+  d == 1
+  e = if a < b then 5 else 6 fi
+  e == 5
+  f = if b < a then 7 else 8 fi
+  f == 8
+  return x

out.code

@@ -0,0 +1,3 @@
+def main(c,a,b):
+	c == (a * b)
+	return 1

src/absy.rs

@@ -195,6 +195,7 @@ impl<T: Field> fmt::Debug for Statement<T> {
 #[derive(Clone, PartialEq, Serialize, Deserialize)]
 pub struct Parameter {
     pub id: String,
+    pub private: bool,
 }
 
 impl fmt::Display for Parameter {

src/flatten.rs

@@ -424,6 +424,7 @@ impl Flattener {
                     match param_expr.apply_substitution(&self.substitution) {
                         Expression::Identifier(ref x) => params_flattened.push(Parameter {
                             id: x.clone().to_string(),
+                            private: false
                         }),
                         _ => {
                             let expr_subbed = param_expr.apply_substitution(&self.substitution);
@@ -439,6 +440,7 @@ impl Flattener {
                                 .push(Statement::Definition(intermediate_var.clone(), rhs));
                             params_flattened.push(Parameter {
                                 id: intermediate_var.clone().to_string(),
+                                private: false
                             });
                         }
                     }
@@ -626,6 +628,7 @@ impl Flattener {
         for arg in funct.arguments {
             arguments_flattened.push(Parameter {
                 id: arg.id.to_string(),
+                private: arg.private
             });
         }
         // flatten statements in functions and apply substitution

src/parser.rs

@@ -150,6 +150,7 @@ enum Token<T: Field> {
     Mult,
     Div,
     Pow,
+    Private,
     Ide(String),
     Num(T),
     Unknown(String),
@@ -188,6 +189,7 @@ impl<T: Field> fmt::Display for Token<T> {
             Token::Mult => write!(f, "*"),
             Token::Div => write!(f, "/"),
             Token::Pow => write!(f, "**"),
+            Token::Private => write!(f, "private"),
             Token::Ide(ref x) => write!(f, "{}", x),
             Token::Num(ref x) => write!(f, "{}", x),
             Token::Unknown(ref x) => write!(f, "{}", x),
@@ -502,6 +504,14 @@ fn next_token<T: Field>(input: &String, pos: &Position) -> (Token<T>, String, Po
                 },
             )
         }
+        Some(_) if input[offset..].starts_with("private ") => (
+            Token::Private,
+            input[offset + 8..].to_string(),
+            Position {
+                line: pos.line,
+                col: pos.col + offset + 8,
+            },
+        ),
         Some(x) => match x {
             '0'...'9' => parse_num(
                 &input[offset..].to_string(),
@@ -1132,8 +1142,55 @@ fn parse_function<T: Field>(
                     let mut p = p3;
                     loop {
                         match next_token(&s, &p) {
+                            (Token::Private, s4, p4) => {
+                                match next_token(&s4, &p4) {
+                                    (Token::Ide(x), s5, p5) => {
+                                        args.push(Parameter { id: x, private: true });
+                                        match next_token(&s5, &p5) {
+                                            (Token::Comma, s6, p6) => {
+                                                s = s6;
+                                                p = p6;
+                                            }
+                                            (Token::Close, s5, p5) => match next_token(&s5, &p5) {
+                                                (Token::Colon, s6, p6) => match next_token(&s6, &p6) {
+                                                    (Token::InlineComment(_), _, _) => break,
+                                                    (Token::Unknown(ref x6), ..) if x6 == "" => break,
+                                                    (t6, _, p6) => {
+                                                        return Err(Error {
+                                                            expected: vec![Token::Unknown("".to_string())],
+                                                            got: t6,
+                                                            pos: p6,
+                                                        })
+                                                    }
+                                                },
+                                                (t6, _, p6) => {
+                                                    return Err(Error {
+                                                        expected: vec![Token::Colon],
+                                                        got: t6,
+                                                        pos: p6,
+                                                    })
+                                                }
+                                            },
+                                            (t5, _, p5) => {
+                                                return Err(Error {
+                                                    expected: vec![Token::Comma, Token::Close],
+                                                    got: t5,
+                                                    pos: p5,
+                                                })
+                                            }
+                                        }
+                                    }
+                                    (t5, _, p5) => {
+                                        return Err(Error {
+                                            expected: vec![Token::Comma, Token::Close],
+                                            got: t5,
+                                            pos: p5,
+                                        })
+                                    }
+                                }
+                            }
                             (Token::Ide(x), s4, p4) => {
-                                args.push(Parameter { id: x });
+                                args.push(Parameter { id: x, private: false });
                                 match next_token(&s4, &p4) {
                                     (Token::Comma, s5, p5) => {
                                         s = s5;

src/r1cs.rs

@@ -290,7 +290,8 @@ pub fn r1cs_program<T: Field>(
         .iter()
         .find(|x: &&Function<T>| x.id == "main".to_string())
         .unwrap();
-    variables.extend(main.arguments.iter().map(|x| format!("{}", x)));
+    variables.extend(main.arguments.iter().filter(|x| x.private == false).map(|x| format!("{}", x)));
+
     // ~out is added after main's arguments as we want variables (columns)
     // in the r1cs to be aligned like "public inputs | private inputs"
     variables.push("~out".to_string());
@@ -298,6 +299,9 @@ pub fn r1cs_program<T: Field>(
     // position where private part of witness starts
     let private_inputs_offset = variables.len();
 
+    variables.extend(main.arguments.iter().filter(|x| x.private == true).map(|x| format!("{}", x)));
+
+
     for def in &main.statements {
         let mut a_row: Vec<(usize, T)> = Vec::new();
         let mut b_row: Vec<(usize, T)> = Vec::new();

variables.inf

@@ -0,0 +1,4 @@
+Private inputs offset:
+3
+R1CS variable order:
+~one c ~out a b 

verification.key

@@ -0,0 +1,13 @@
+		vk.A = [0x31794eb3a1691cc21bc9c964ee68db7ae28106b82787eef92fcae4a9c0e483, 0x2852286171b3eb1fff063874ef396d5c87d28b156a46a6ced7679780a681925e], [0x23a5d861d726720339f2861a861ee210604638ee1ead2af2c6f625d56cfda2d1, 0x16e92a3994f5a1d5809dcf62cf954fa9ae908a31b3080da065330850e9dfc543]
+		vk.B = 0x2b943f88d3bf0f6e2a822c6403c2c65a1d15450140b3f16a88f57e341c803b9f, 0x1c2dfce4287fb58ffe48044b396f9a988af57f58b778bbe395d73b3ebd40ac52
+		vk.C = [0x17d0522fa7e63bbdbefac9977e8787dbca5493f4d5b8001478944ab0be9474d2, 0x234356e7b44810bda6a4bb5ff7a17f01cd2be0356d1477912a9b97557e428341], [0x14893eb4d934af54b57b983239d5dc3b4074d809a87399f40626d685579d41c, 0x257802281a9aa9825bc886e6d9a0251a82fa50758bcd2677019ef6612e581819]
+		vk.gamma = [0x2ab2532debf0b5223ec3212b4e7b0afd66a3e10b6bc24282ea9780b40b06427b, 0x68d5b8e053f64c547a4363171733e75ca6cb692eaed3fd062bb810b42731e43], [0x15b3a5a27e97d8850ccb7a8f7be16835fd069c8982852ba0a19ca6699fed1f65, 0x3f7228f46f64d11bcba6540de41036d25dcad2b05b3f7066557c0b675692cb7]
+		vk.gammaBeta1 = 0x27602b76a313ceecf3afd6417563cb03de4e74799dd16fef8c28171313679571, 0x10ac0cd595cfdaf433efc2d4464271c62f7dc0f4e3c6b137f11ead282f03f76c
+		vk.gammaBeta2 = [0x12ffa58b224c0656664d1dd439cbb6b339e4f2d28a8efd3592cb418b0bb71e7f, 0x1431c785fb238f1c42f96aed8118b3abb575dc75335435b33f3266eb796ff26c], [0x55e2b2ba927eee3bc8aecbab1a72e1702f692f66b3cfa3c41069dde61ba0649, 0x9fff9db01e86a749b3a7e47767e11fbf10c16dbc8f74379f67af61eeb3c1bba]
+		vk.Z = [0x11b12fe6a6dcd649d8c634e506a4aa176ca70fde632fdfda06b9b28073732517, 0x2646ea2adcd0c0726548ecaa03dae29070f95c286985c8e07c2e18863be619c1], [0x256579f8d1321a4ca8e6a807e103c2e8d08d9b88b930e9b17d4c3313a7454851, 0x225eca3599e7f392017bb5dde4df4c974422e2377828ed91a1a6b56e2f278184]
+		vk.IC.len() = 5
+		vk.IC[0] = 0x1bb9cf704f62808123097642c9fc34dfa360451e8f8dcb6ea438793d45fa082d, 0x11729b4322acb068e76e0db12bf08825c77271879b241908d70ee7597efa4460
+		vk.IC[1] = 0x2644885e567a696deb2169d46cde807af0344e5d29fd86bd2a2fd94ce07fe4a3, 0xde1853871c61add0694c4f0c86575fde5b53e504c9ae799f54726c096f5496e
+		vk.IC[2] = 0x1abeee45d3bb30bc7f335e4e118ce7c50252e7f5998efafe1d68b1582fd0bdeb, 0x267ff3cc655bdf4aa2eb413fd64d6782af4d763670ec3c984e36a1c10bad7064
+		vk.IC[3] = 0x28f8d04e1314fff7541495e1798bd3d9e16e59c6744e42747cd71032979f6fb9, 0x2f696b7f7a693e24461c733af0252bbb55ad38af1341d98bc1e5fe1470acd13b
+		vk.IC[4] = 0x100dfc176ee1c80cb185857765fe74db10cf2b967ea9cf09e75955a9d3d72475, 0x2d391ecaaefbb947add78ed0ad7f2d9efec162aef33779027016018ba8c799f6

witness

@@ -0,0 +1,5 @@
+~out 1
+a 2
+~one 1
+c 8
+b 4