add allow import circuits in circuits language compiler

circuitcompiler/circuit-test-1.circuit

@@ -0,0 +1,8 @@
+import "circuit-test-2.circuit"
+
+func main(private s0, public s1):
+	s3 = exp3(s0)
+	s4 = sum(s3, s0)
+	s5 = s4 + 5
+	equals(s1, s5)
+	out = 1 * 1

circuitcompiler/circuit-test-2.circuit

@@ -0,0 +1,7 @@
+func exp3(private a):
+	b = a * a
+	c = a * b
+	return c
+func sum(private a, private b):
+	c = a + b
+	return c

circuitcompiler/circuit_test.go

@@ -1,7 +1,9 @@
 package circuitcompiler
 
 import (
+	"bufio"
 	"math/big"
+	"os"
 	"strings"
 	"testing"
 
@@ -172,3 +174,75 @@ func TestCircuitWithFuncCallsParser(t *testing.T) {
 	assert.Equal(t, len(circuit.PublicInputs), 1)
 	assert.Equal(t, len(circuit.PrivateInputs), 1)
 }
+
+func TestCircuitFromFileWithImports(t *testing.T) {
+	circuitFile, err := os.Open("./circuit-test-1.circuit")
+	assert.Nil(t, err)
+
+	parser := NewParser(bufio.NewReader(circuitFile))
+	circuit, err := parser.Parse()
+	assert.Nil(t, err)
+
+	// flat code to R1CS
+	a, b, c := circuit.GenerateR1CS()
+	assert.Equal(t, "s0", circuit.PrivateInputs[0])
+	assert.Equal(t, "s1", circuit.PublicInputs[0])
+
+	assert.Equal(t, []string{"one", "s1", "s0", "b0", "s3", "s4", "s5", "out"}, circuit.Signals)
+
+	// expected result
+	b0 := big.NewInt(int64(0))
+	b1 := big.NewInt(int64(1))
+	b5 := big.NewInt(int64(5))
+	aExpected := [][]*big.Int{
+		[]*big.Int{b0, b0, b1, b0, b0, b0, b0, b0},
+		[]*big.Int{b0, b0, b1, b0, b0, b0, b0, b0},
+		[]*big.Int{b0, b0, b1, b0, b1, b0, b0, b0},
+		[]*big.Int{b5, b0, b0, b0, b0, b1, b0, b0},
+		[]*big.Int{b0, b0, b0, b0, b0, b0, b1, b0},
+		[]*big.Int{b0, b1, b0, b0, b0, b0, b0, b0},
+		[]*big.Int{b1, b0, b0, b0, b0, b0, b0, b0},
+	}
+	bExpected := [][]*big.Int{
+		[]*big.Int{b0, b0, b1, b0, b0, b0, b0, b0},
+		[]*big.Int{b0, b0, b0, b1, b0, b0, b0, b0},
+		[]*big.Int{b1, b0, b0, b0, b0, b0, b0, b0},
+		[]*big.Int{b1, b0, b0, b0, b0, b0, b0, b0},
+		[]*big.Int{b1, b0, b0, b0, b0, b0, b0, b0},
+		[]*big.Int{b1, b0, b0, b0, b0, b0, b0, b0},
+		[]*big.Int{b1, b0, b0, b0, b0, b0, b0, b0},
+	}
+	cExpected := [][]*big.Int{
+		[]*big.Int{b0, b0, b0, b1, b0, b0, b0, b0},
+		[]*big.Int{b0, b0, b0, b0, b1, b0, b0, b0},
+		[]*big.Int{b0, b0, b0, b0, b0, b1, b0, b0},
+		[]*big.Int{b0, b0, b0, b0, b0, b0, b1, b0},
+		[]*big.Int{b0, b1, b0, b0, b0, b0, b0, b0},
+		[]*big.Int{b0, b0, b0, b0, b0, b0, b1, b0},
+		[]*big.Int{b0, b0, b0, b0, b0, b0, b0, b1},
+	}
+
+	assert.Equal(t, aExpected, a)
+	assert.Equal(t, bExpected, b)
+	assert.Equal(t, cExpected, c)
+
+	b3 := big.NewInt(int64(3))
+	privateInputs := []*big.Int{b3}
+	b35 := big.NewInt(int64(35))
+	publicInputs := []*big.Int{b35}
+	// Calculate Witness
+	w, err := circuit.CalculateWitness(privateInputs, publicInputs)
+	assert.Nil(t, err)
+	b9 := big.NewInt(int64(9))
+	b27 := big.NewInt(int64(27))
+	b30 := big.NewInt(int64(30))
+	wExpected := []*big.Int{b1, b35, b3, b9, b27, b30, b35, b1}
+	assert.Equal(t, wExpected, w)
+
+	// circuitJson, _ := json.Marshal(circuit)
+	// fmt.Println("circuit:", string(circuitJson))
+
+	assert.Equal(t, circuit.NPublic, 1)
+	assert.Equal(t, len(circuit.PublicInputs), 1)
+	assert.Equal(t, len(circuit.PrivateInputs), 1)
+}

circuitcompiler/parser.go

@@ -1,6 +1,7 @@
 package circuitcompiler
 
 import (
+	"bufio"
 	"errors"
 	"fmt"
 	"io"
@@ -117,6 +118,19 @@ func (p *Parser) parseLine() (*Constraint, error) {
 		c.Out = varToReturn
 		return c, nil
 	}
+	if c.Literal == "import" {
+		line, err := p.s.r.ReadString('\n')
+		if err != nil {
+			return c, err
+		}
+		// read string inside " "
+		path := strings.TrimLeft(strings.TrimRight(line, `"`), `"`)
+		path = strings.Replace(path, `"`, "", -1)
+		path = strings.Replace(path, " ", "", -1)
+		path = strings.Replace(path, "\n", "", -1)
+		c.Out = path
+		return c, nil
+	}
 
 	_, lit = p.scanIgnoreWhitespace() // skip =
 	c.Literal += lit
@@ -302,6 +316,15 @@ func (p *Parser) Parse() (*Circuit, error) {
 			continue
 
 		}
+		if constraint.Literal == "import" {
+			circuitFile, err := os.Open(constraint.Out)
+			if err != nil {
+				panic(errors.New("imported path error: " + constraint.Out))
+			}
+			parser := NewParser(bufio.NewReader(circuitFile))
+			_, err = parser.Parse() // this will add the imported file funcs into the `circuits` map
+			continue
+		}
 
 		circuits[currCircuit].Constraints = append(circuits[currCircuit].Constraints, *constraint)
 		isVal, _ := isValue(constraint.V1)