Merge pull request #917 from Zokrates/field-size-in-bits

Add FIELD_SIZE_IN_BITS constant to EMBED

changelogs/unreleased/917-dark64

@@ -0,0 +1 @@
+Add `FIELD_SIZE_IN_BITS`, `FIELD_MIN` and `FIELD_MAX` constants to `field` stdlib module

zokrates_core/src/imports.rs

@@ -14,6 +14,7 @@ use std::fmt;
 use std::io;
 use std::path::{Path, PathBuf};
 
+use crate::absy::types::UnresolvedType;
 use typed_arena::Arena;
 use zokrates_common::Resolver;
 use zokrates_field::{Bn128Field, Field};
@@ -156,6 +157,17 @@ impl Importer {
                     id: symbol.get_alias(),
                     symbol: Symbol::Flat(FlatEmbed::U8FromBits),
                 },
+                "FIELD_SIZE_IN_BITS" => SymbolDeclaration {
+                    id: symbol.get_alias(),
+                    symbol: Symbol::Here(SymbolDefinition::Constant(
+                        ConstantDefinition {
+                            ty: UnresolvedType::Uint(32).into(),
+                            expression: Expression::U32Constant(T::get_required_bits() as u32)
+                                .into(),
+                        }
+                        .start_end(pos.0, pos.1),
+                    )),
+                },
                 s => {
                     return Err(CompileErrorInner::ImportError(
                         Error::new(format!("Embed {} not found", s)).with_pos(Some(pos)),

zokrates_core_test/tests/tests/cached_condition.json

@@ -1,4 +1,5 @@
 {
-	"entry_point": "./tests/tests/cached_condition.zok",
-    "max_constraint_count": 2015
+  "entry_point": "./tests/tests/cached_condition.zok",
+  "max_constraint_count": 2015,
+  "tests": []
 }

zokrates_stdlib/stdlib/field.zok

@@ -0,0 +1,8 @@
+from "EMBED" import FIELD_SIZE_IN_BITS
+
+const field FIELD_MIN = 0
+const field FIELD_MAX = -1
+
+// A dummy `main` function, should NOT be used.
+def main():
+    return

zokrates_stdlib/tests/tests/field.json

@@ -0,0 +1,17 @@
+{
+    "entry_point": "./tests/tests/field.zok",
+    "max_constraint_count": 3,
+    "curves": ["Bn128"],
+    "tests": [
+        {
+            "input": {
+                "values": []
+            },
+            "output": {
+                "Ok": {
+                    "values": ["0", "21888242871839275222246405745257275088548364400416034343698204186575808495616", "254"]
+                }
+            }
+        }
+    ]
+}

zokrates_stdlib/tests/tests/field.zok

@@ -0,0 +1,4 @@
+from "field" import FIELD_MIN, FIELD_MAX, FIELD_SIZE_IN_BITS
+
+def main() -> (field, field, u32):
+    return FIELD_MIN, FIELD_MAX, FIELD_SIZE_IN_BITS