Chapter 17: Syntax Sugarlinear-chapter17

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diff --git a/src/test/java/com/seaofnodes/simple/Chapter17Test.java b/src/test/java/com/seaofnodes/simple/Chapter17Test.java
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+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.evaluator.Evaluator;
+import com.seaofnodes.simple.node.StopNode;
+import org.junit.Test;
+import org.junit.Ignore;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class Chapter17Test {
+
+    @Test
+    public void testJig() {
+        Parser parser = new Parser("""
+int i = 0;
+i=i=1;
+return i;
+                                   //return 3.14;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 1;", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop,  0));
+    }
+
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testInc0() {
+        Parser parser = new Parser("""
+return arg++;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return arg;", stop.toString());
+        assertEquals(0L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test
+    public void testInc1() {
+        Parser parser = new Parser("""
+return arg+++arg++;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return ((arg*2)+1);", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test
+    public void testInc2() {
+        Parser parser = new Parser("""
+//   -(arg--)-(arg--)
+return -arg---arg--;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return (-((arg*2)+-1));", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test
+    public void testInc3() {
+        Parser parser = new Parser("""
+int[] !xs = new int[arg];
+xs[0]++;
+xs[1]++;
+return xs[0];
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 1;", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop, 2));
+    }
+
+    @Test
+    public void testInc4() {
+        Parser parser = new Parser("""
+u8[] !xs = new u8[1];
+xs[0]--;
+return xs[0];
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 255;", stop.toString());
+        assertEquals(255L, Evaluator.evaluate(stop, 2));
+    }
+
+    @Test
+    public void testInc5() {
+        Parser parser = new Parser("""
+struct S { u16 x; };
+S !s = new S;
+s.x--;
+return s.x;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 65535;", stop.toString());
+        assertEquals(65535L, Evaluator.evaluate(stop, 2));
+    }
+
+    @Test
+    public void testInc6() {
+        Parser parser = new Parser("return --arg;");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return (arg+-1);", stop.toString());
+        assertEquals(-1L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test
+    public void testInc7() {
+        Parser parser = new Parser("u8 x=0; return --x;");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 255;", stop.toString());
+        assertEquals(255L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test
+    public void testInc8() {
+        Parser parser = new Parser("int x; x+=2; return x+=3;");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 5;", stop.toString());
+        assertEquals(5L, Evaluator.evaluate(stop, 0));
+    }
+
+    // ---------------------------------------------------------------
+    @Test public void testVar0() {
+        Parser parser = new Parser("var d; return d;");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Syntax error, expected =expression: ;",e.getMessage()); }
+    }
+
+    @Test public void testVar1() {
+        Parser parser = new Parser("val d; return d;");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Syntax error, expected =expression: ;",e.getMessage()); }
+    }
+
+    @Test public void testVar2() {
+        Parser parser = new Parser("int x; x=3; x++; return x; // Ok, no initializer so x is mutable ");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 4;", stop.toString());
+        assertEquals(4L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test public void testVar3() {
+        Parser parser = new Parser("int x=3; x++; return x; // Ok, primitive so x is mutable despite initializer ");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 4;", stop.toString());
+        assertEquals(4L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test public void testVar4() {
+        Parser parser = new Parser("struct S{int x;}; S s; s=new S; s.x++; return s.x; // Ok, no initializer so x is mutable ");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 1;", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test public void testVar5() {
+        Parser parser = new Parser("struct S{int x;}; S s; s=new S{x=3;}; s.x++; return s.x; // Ok, no initializer so x is mutable ");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 4;", stop.toString());
+        assertEquals(4L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test public void testVar6() {
+        Parser parser = new Parser("struct S{int x;}; S s=new S; s.x++; return s.x; // Error initializer so x is immutable ");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test public void testVar7() {
+        Parser parser = new Parser("struct S{int x;}; S s=new S{x=3;}; s.x++; return s.x; // Error initializer so x is immutable ");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test public void testVar8() {
+        Parser parser = new Parser("struct S{int x;}; S !s=new S; s.x++; return s.x; // Ok, has '!' so s.x is mutable ");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 1;", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test public void testVar9() {
+        Parser parser = new Parser("struct S{int x;}; var s=new S; s.x++; return s.x; // Ok, has var so s.x is mutable ");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 1;", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test public void testVar10() {
+        Parser parser = new Parser("struct S{int x;}; val s=new S; s.x++; return s.x; // Error, has val so x is immutable ");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test public void testVar11() {
+        Parser parser = new Parser("""
+struct Bar { int x; };
+Bar !bar = new Bar;
+bar.x = 3; // Ok, bar is mutable
+
+struct Foo { Bar? !bar; int y; };
+Foo !foo = new Foo { bar = bar; };
+foo.bar = bar; // Ok foo is mutable
+foo.bar.x++;   // Ok foo and foo.bar and foo.bar.x are all mutable
+
+val xfoo = foo; // Throw away mutability
+xfoo.bar.x++;   // Error, cannot mutate through xfoo
+ """);
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot modify final field 'x'",e.getMessage()); }
+    }
+
+    @Test public void testVar12() {
+        Parser parser = new Parser("""
+struct Bar { int x; };
+Bar !bar = new Bar;
+bar.x = 3; // Ok, bar is mutable
+
+struct Foo { Bar? !bar; int y; };
+Foo !foo = new Foo;
+foo.bar = bar; // Ok bar is mutable
+foo.bar.x++;   // Ok foo and foo.bar and foo.bar.x are all mutable
+
+val xfoo = foo;        // Throw away mutability
+int x4 = xfoo.bar.x;   // Ok to read through xfoo, gets 4
+foo.bar.x++;           // Bumps to 5
+int x5 = xfoo.bar.x;   // Ok to read through xfoo, gets 5
+return x4*10+x5;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 45;", stop.toString());
+        assertEquals(45L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test
+    public void testVar13() {
+        Parser parser = new Parser("""
+int i,i++;
+""");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Redefining name 'i'",e.getMessage()); }
+    }
+
+
+    @Test
+    public void testVar14() {
+        Parser parser = new Parser("""
+struct B {};
+struct A { B b; };
+A x = new A {
+    return b; // read before init
+    b = new B;
+};
+""");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Cannot read uninitialized field 'b'",e.getMessage()); }
+    }
+
+    @Test
+    public void testVar15() {
+        Parser parser = new Parser("""
+struct B {};
+struct A { B b; };
+return new A {
+    if (arg) b = new B; // Constructor ends with partial init of b
+}.b;
+""");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("'A' is not fully initialized, field 'b' needs to be set in a constructor",e.getMessage()); }
+    }
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testTrinary0() {
+        Parser parser = new Parser("""
+return arg ? 1 : 2;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Region,1,2);", stop.toString());
+        assertEquals(2L, Evaluator.evaluate(stop, 0));
+        assertEquals(1L, Evaluator.evaluate(stop, 1));
+    }
+
+    @Test
+    public void testTrinary1() {
+        Parser parser = new Parser("""
+return arg ? 0 : arg;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return 0;", stop.toString());
+        assertEquals(0L, Evaluator.evaluate(stop, 0));
+    }
+
+    @Test
+    public void testTrinary2() {
+        Parser parser = new Parser("""
+struct Bar { int x; };
+var b = arg ? new Bar : null;
+return b ? b.x++ + b.x++ : -1;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Region,1,-1);", stop.toString());
+        assertEquals(-1L, Evaluator.evaluate(stop, 0));
+        assertEquals( 1L, Evaluator.evaluate(stop, 1));
+    }
+
+    @Test
+    public void testTrinary3() {
+        Parser parser = new Parser("""
+struct Bar { int x; };
+var b = arg ? new Bar;
+return b ? b.x++ + b.x++ : -1;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Region,1,-1);", stop.toString());
+        assertEquals(-1L, Evaluator.evaluate(stop, 0));
+        assertEquals( 1L, Evaluator.evaluate(stop, 1));
+    }
+
+    @Test
+    public void testTrinary4() {
+        // This test case will benefit from an unzipping transformation
+        Parser parser = new Parser("""
+struct Bar { Bar? next; int x; };
+var b = arg ? new Bar { next = (arg==2) ? new Bar{x=2;}; x=1; };
+return b ? b.next ? b.next.x : b.x; // parses "b ? (b.next ? b.next.x : b.x) : 0"
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Region,Phi(Region,.x,.x),0);", stop.toString());
+        assertEquals( 0L, Evaluator.evaluate(stop, 0));
+        assertEquals( 1L, Evaluator.evaluate(stop, 1));
+        assertEquals( 2L, Evaluator.evaluate(stop, 2));
+    }
+
+    @Test
+    public void testTrinary5() {
+        Parser parser = new Parser("""
+flt f=arg?1:1.2;
+return f;   // missing widening
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Region,1.0,1.2);", stop.toString());
+        assertEquals(1.2, Evaluator.evaluate(stop,  0));
+    }
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testFor0() {
+        Parser parser = new Parser("""
+int sum=0;
+for( int i=0; i<arg; i++ )
+    sum += i;
+return sum;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Loop,0,(Phi_sum+Phi(Loop,0,(Phi_i+1))));", stop.toString());
+        assertEquals(3L, Evaluator.evaluate(stop, 3));
+        assertEquals(45L, Evaluator.evaluate(stop, 10));
+    }
+    @Test
+    public void testFor1() {
+        Parser parser = new Parser("""
+int sum=0, i=0;
+for( ; i<arg; i++ )
+    sum += i;
+return sum;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Loop,0,(Phi_sum+Phi(Loop,0,(Phi_i+1))));", stop.toString());
+        assertEquals(3L, Evaluator.evaluate(stop, 3));
+        assertEquals(45L, Evaluator.evaluate(stop, 10));
+    }
+    @Test
+    public void testFor2() {
+        Parser parser = new Parser("""
+int sum=0;
+for( int i=0; ; i++ ) {
+    if( i>=arg ) break;
+    sum += i;
+}
+return sum;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Loop,0,(Phi_sum+Phi(Loop,0,(Phi_i+1))));", stop.toString());
+        assertEquals(3L, Evaluator.evaluate(stop, 3));
+        assertEquals(45L, Evaluator.evaluate(stop, 10));
+    }
+    @Test
+    public void testFor3() {
+        Parser parser = new Parser("""
+int sum=0;
+for( int i=0; i<arg; )
+    sum += i++;
+return sum;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Loop,0,(Phi_sum+Phi(Loop,0,(Phi_i+1))));", stop.toString());
+        assertEquals(3L, Evaluator.evaluate(stop, 3));
+        assertEquals(45L, Evaluator.evaluate(stop, 10));
+    }
+    @Test
+    public void testFor4() {
+        Parser parser = new Parser("""
+int sum=0;
+for( int i=0; i<arg; i++ )
+    sum += i;
+return i;
+""");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Undefined name 'i'",e.getMessage()); }
+    }
+    @Test
+    public void testFor5() {
+        Parser parser = new Parser("""
+for(;;arg++;) {}
+""");
+        try { parser.parse().iterate(); fail(); }
+        catch( Exception e ) { assertEquals("Syntax error, expected Unexpected code after expression: ;",e.getMessage()); }
+    }
+
+
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testForward0() {
+        Parser parser = new Parser("""
+struct A{
+    B? f1;
+    B? f2;
+};
+return new A;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return A;", stop.toString());
+        assertEquals("Obj<A>{f1=null,f2=null}", Evaluator.evaluate(stop).toString());
+    }
+
+    @Test
+    public void testForward1() {
+        Parser parser = new Parser("""
+struct A{
+    B?[]? nil_array_of_b;
+    B?[]  not_array_of_b = new B?[0];
+};
+return new A.not_array_of_b;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return (const)[*B?];", stop.toString());
+        assertEquals("Obj<[*B?]>{#=0,[]=[]}", Evaluator.evaluate(stop).toString());
+    }
+
+    // ---------------------------------------------------------------
+    @Test
+    public void testLinkedList2() {
+        Parser parser = new Parser("""
+struct LLI { LLI? next; int i; };
+LLI? !head = null;
+while( arg-- )
+    head = new LLI { next=head; i=arg; };
+int sum=0;
+var ptr = head; // A read-only ptr, to be assigned from read-only next fields
+for( ; ptr; ptr = ptr.next )
+    sum += ptr.i;
+return sum;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return Phi(Loop,0,(Phi_sum+.i));", stop.toString());
+        assertEquals(45L, Evaluator.evaluate(stop, 10));
+    }
+
+    @Test
+    public void sieveOfEratosthenes() {
+        Parser parser = new Parser(
+"""
+var ary = new bool[arg], primes = new int[arg];
+var nprimes=0, p=0;
+// Find primes while p^2 < arg
+for( p=2; p*p < arg; p++ ) {
+    // skip marked non-primes
+    while( ary[p] ) p++;
+    // p is now a prime
+    primes[nprimes++] = p;
+    // Mark out the rest non-primes
+    for( int i = p + p; i < ary#; i += p )
+        ary[i] = true;
+}
+// Now just collect the remaining primes, no more marking
+for( ; p < arg; p++ )
+    if( !ary[p] )
+        primes[nprimes++] = p;
+// Copy/shrink the result array
+var !rez = new int[nprimes];
+for( int j=0; j<nprimes; j++ )
+    rez[j] = primes[j];
+return rez;
+""");
+        StopNode stop = parser.parse().iterate();
+        assertEquals("return [int];", stop.toString());
+        Evaluator.Obj obj = (Evaluator.Obj)Evaluator.evaluate(stop, 20);
+        assertEquals("[int] {int #; int ![]; }",obj.struct().toString());
+        long nprimes = (Long)obj.fields()[0];
+        long[] primes = new long[]{2,3,5,7,11,13,17,19};
+        for( int i=0; i<nprimes; i++ )
+            assertEquals(primes[i],(long)(Long)obj.fields()[i+1]);
+    }
+
+}