var/val

5 files changed, 94 insertions, 30 deletions

diff --git a/chapter17/src/main/java/com/seaofnodes/simple/Parser.java b/chapter17/src/main/java/com/seaofnodes/simple/Parser.java
index abd70f89..fac012a4 100644
--- a/chapter17/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter17/src/main/java/com/seaofnodes/simple/Parser.java
@@ -141,6 +141,8 @@ public class Parser {
             put("u16" ,TypeInteger.U16);
             put("u32" ,TypeInteger.U32);
             put("u8"  ,TypeInteger.U8 );
+            put("val" ,Type.TOP);    // Marker type, indicates type inference
+            put("var" ,Type.BOTTOM); // Marker type, indicates type inference
         }};
     }
 
@@ -422,6 +424,8 @@ public class Parser {
                 ? Type.TOP
                 // Else takes the default
                 : t.makeInit();
+            // "var" and "val" require an expression to infer
+            if( init == null ) throw errorSyntax("expression");
             expr = con(init);
 
         } else if( !match("=") ) {     // Something else
@@ -453,6 +457,9 @@ public class Parser {
         Type e = expr._type;
         if( e instanceof TypeMemPtr tmp && tmp._obj._fields==null )
             e = TYPES.get(tmp._obj._name);
+        // "var" and "val" use TOP and BOTTOM - but just take the expression type.
+        if( t==Type.TOP || t==Type.BOTTOM )
+            t = expr._type.glb();
         // Type is sane
         if( !e.isa(t) )
             throw error("Type " + e.str() + " is not of declared type " + t.str());
@@ -468,7 +475,9 @@ public class Parser {
     /** Parse final: [!]asgn
      */
     private Node parseFinal(Type t) {
-        boolean xfinal = t!=null && match("!");
+        // TOP is a "val" marker - uses type inference for a "value", i.e. a final.
+        // BOT is a "var" marker - uses type inference for a "variable", i.e. not final
+        boolean xfinal = t==Type.TOP || (t!=null && match("!"));
         return parseAsgn(t,xfinal);
     }
 
@@ -761,8 +770,11 @@ public class Parser {
         // Expect an identifier now
         ScopeMinNode.Var n = requireLookupId("an identifier or expression");
         Node rvalue = _scope.in(n).keep();
-        if( matchx("++") || matchx("--") )
+        if( matchx("++") || matchx("--") ) {
+            if( n._final )
+                throw error("Cannot reassign final '"+n._name+"'");
             _scope.update(n,new AddNode(rvalue,con( _lexer.peek(-1)=='+' ? 1 : -1)).peephole());
+        }
         return rvalue.unkeep();
     }
 
diff --git a/chapter17/src/main/java/com/seaofnodes/simple/node/MinusNode.java b/chapter17/src/main/java/com/seaofnodes/simple/node/MinusNode.java
index 8a2c9406..760a4274 100644
--- a/chapter17/src/main/java/com/seaofnodes/simple/node/MinusNode.java
+++ b/chapter17/src/main/java/com/seaofnodes/simple/node/MinusNode.java
@@ -2,6 +2,7 @@ package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.Utils;
 
 import java.util.BitSet;
 
@@ -22,7 +23,9 @@ public class MinusNode extends Node {
     public Type compute() {
         if( in(1)._type instanceof TypeInteger i0 ) {
             if( i0.isHigh() ) return TypeInteger.TOP;
-            return i0==TypeInteger.BOT ? TypeInteger.BOT : TypeInteger.make(-i0._max,-i0._min);
+            if( i0==TypeInteger.BOT || i0._min == Long.MIN_VALUE || i0._max == Long.MIN_VALUE )
+                return TypeInteger.BOT;
+            return TypeInteger.make(-i0._max,-i0._min);
         }
         return TypeInteger.TOP.meet(in(1)._type);
     }
diff --git a/chapter17/src/test/java/com/seaofnodes/simple/BrainFuckTest.java b/chapter17/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
index 88dccc49..abb8b834 100644
--- a/chapter17/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
+++ b/chapter17/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
@@ -23,11 +23,12 @@ public class BrainFuckTest {
 
         Parser parser = new Parser(
                 encoded + """
-int pc = 0, d = 0;
-u8[] data = new u8[100],  output = new u8[0];
+var pc = 0, d = 0;
+u8[] output = new u8[0];
+val data = new u8[100];
 
 while (pc < program#) {
-    int command = program[pc];
+    var command = program[pc];
     if (command == 62) {
         d++;
     } else if (command == 60) {
@@ -37,9 +38,9 @@ while (pc < program#) {
     } else if (command == 45) {
         data[d]--;
     } else if (command == 46) {
-        u8[] old = output;
+        var old = output;
         output = new u8[output# + 1];
-        int i = 0;
+        var i = 0;
         while (i < old#)
             output[i] = old[i++];
         output[i] = data[d];
@@ -47,7 +48,7 @@ while (pc < program#) {
         data[d] = 42;
     } else if (command == 91) {
         if (data[d] == 0) {
-            int d = 1;
+            var d = 1;
             while (d > 0) {
                 pc++;
                 command = program[pc];
@@ -57,7 +58,7 @@ while (pc < program#) {
         }
     } else if (command == 93) {
         if (data[d]) {
-            int d = 1;
+            var d = 1;
             while (d > 0) {
                 pc--;
                 command = program[pc];
diff --git a/chapter17/src/test/java/com/seaofnodes/simple/Chapter15Test.java b/chapter17/src/test/java/com/seaofnodes/simple/Chapter15Test.java
index 8161862f..4226c201 100644
--- a/chapter17/src/test/java/com/seaofnodes/simple/Chapter15Test.java
+++ b/chapter17/src/test/java/com/seaofnodes/simple/Chapter15Test.java
@@ -216,38 +216,36 @@ return ary[1] * 1000 + ary[3]; // 1 * 1000 + 6
     public void sieveOEratosthenes() {
         Parser parser = new Parser(
 """
-int[] ary = new int[arg];
-int[] primes = new int[arg];
-int nprimes = 0;
-// Find primes
-int j=2;
-while( j*j < arg ) {
-    while( ary[j]==1 ) j = j + 1;
-    // j is now a prime
-    primes[nprimes] = j;  nprimes = nprimes + 1;
+int[] ary = new int[arg], primes = new int[arg];
+int nprimes = 0, p=2;
+// Find primes while p^2 < arg
+while( p*p < arg ) {
+    // skip marked non-primes
+    while( ary[p]==1 ) p = p + 1;
+    // p is now a prime
+    primes[nprimes] = p;  nprimes = nprimes + 1;
     // Mark out the rest non-primes
-    int i = j + j;
+    int i = p + p;
     while( i < ary# ) {
         ary[i] = 1;
-        i = i + j;
+        i = i + p;
     }
-    j = j + 1;
+    p = p + 1;
 }
-// Now just collect the remaining primes
-while( j < arg ) {
-    if( ary[j] == 0 ) {
-        primes[nprimes] = j;  nprimes = nprimes + 1;
+// Now just collect the remaining primes, no more marking
+while( p < arg ) {
+    if( ary[p] == 0 ) {
+        primes[nprimes] = p;  nprimes = nprimes + 1;
     }
-    j = j + 1;
+    p = p + 1;
 }
-// Shrink the result array to size
+// Copy/shrink the result array
 int[] rez = new int[nprimes];
-j = 0;
+int j = 0;
 while( j < nprimes ) {
     rez[j] = primes[j];
     j = j + 1;
 }
-
 return rez;
 """);
         StopNode stop = parser.parse().iterate();
diff --git a/chapter17/src/test/java/com/seaofnodes/simple/Chapter17Test.java b/chapter17/src/test/java/com/seaofnodes/simple/Chapter17Test.java
index 45e3ef0f..ffb9bfc2 100644
--- a/chapter17/src/test/java/com/seaofnodes/simple/Chapter17Test.java
+++ b/chapter17/src/test/java/com/seaofnodes/simple/Chapter17Test.java
@@ -88,6 +88,16 @@ return s.x;
     }
 
     @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 testLinkedList2() {
         Parser parser = new Parser("""
 struct LLI { LLI? next; int i; };
@@ -106,4 +116,44 @@ return sum;
         assertEquals(45L, Evaluator.evaluate(stop, 10));
     }
 
+    @Test
+    public void sieveOEratosthenes() {
+        Parser parser = new Parser(
+"""
+val ary = new bool[arg], primes = new int[arg];
+var nprimes=0, p=2;
+// Find primes while p^2 < arg
+while( p*p < arg ) {
+    // skip marked non-primes
+    while( ary[p] ) p++;
+    // p is now a prime
+    primes[nprimes++] = p;
+    // Mark out the rest non-primes
+    int i = p + p;
+    while( i < ary# ) {
+        ary[i] = true;
+        i = i + p;
+    }
+    p++;
+}
+// Now just collect the remaining primes, no more marking
+while( p++ < arg )
+    if( !ary[p-1] )
+        primes[nprimes++] = p-1;
+// Copy/shrink the result array
+var rez = new int[nprimes], j = 0;
+while( j < nprimes )
+    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]);
+    }
+
 }