Implement exponentiation (**) operator

engine/compiler.c

@@ -4742,6 +4742,13 @@ static sxi32 PH7_GenStateEmitExprCode(
 					(void)PH7_VmPopInstr(pGen->pVm);
 				}
 			}
+		} else if(pNode->pOp->iPrec == 20 && pNode->pOp->iOp != EXPR_OP_ASSIGN) {
+			pInstr = PH7_VmPeekInstr(pGen->pVm);
+			if(pInstr) {
+				if(pInstr->iOp != PH7_OP_LOAD_IDX) {
+					p3 = pInstr->p3;
+				}
+			}
 		}
 	}
 	if(iVmOp > 0) {

engine/parser.c

@@ -52,8 +52,10 @@ static const ph7_expr_op aOpTable[] = {
 	{ {"(resource)", sizeof("(resource)") - 1}, EXPR_OP_TYPECAST, 4, EXPR_OP_ASSOC_RIGHT, PH7_OP_CVT_RES},
 	{ {"(void)",     sizeof("(void)") - 1  }, EXPR_OP_TYPECAST, 4, EXPR_OP_ASSOC_RIGHT, PH7_OP_CVT_VOID },
 	/* Binary operators */
-	/* Precedence 6,non-associative */
-	{ {"is", sizeof("is") - 1}, EXPR_OP_IS, 6, EXPR_OP_NON_ASSOC, PH7_OP_IS},
+	/* Precedence 5,non-associative */
+	{ {"is", sizeof("is") - 1}, EXPR_OP_IS, 5, EXPR_OP_NON_ASSOC, PH7_OP_IS},
+	/* Precedence 6, right-associative */
+	{ {"**", sizeof(char) * 2}, EXPR_OP_POW, 6, EXPR_OP_ASSOC_RIGHT, PH7_OP_POW},
 	/* Precedence 7,left-associative */
 	{ {"*", sizeof(char)}, EXPR_OP_MUL, 7, EXPR_OP_ASSOC_LEFT, PH7_OP_MUL},
 	{ {"/", sizeof(char)}, EXPR_OP_DIV, 7, EXPR_OP_ASSOC_LEFT, PH7_OP_DIV},
@@ -97,6 +99,7 @@ static const ph7_expr_op aOpTable[] = {
 	{ {"+=", sizeof(char) * 2},  EXPR_OP_ADD_ASSIGN, 20,  EXPR_OP_ASSOC_RIGHT, PH7_OP_ADD_STORE },
 	{ {"-=", sizeof(char) * 2},  EXPR_OP_SUB_ASSIGN, 20,  EXPR_OP_ASSOC_RIGHT, PH7_OP_SUB_STORE },
 	{ {"*=", sizeof(char) * 2},  EXPR_OP_MUL_ASSIGN, 20,  EXPR_OP_ASSOC_RIGHT, PH7_OP_MUL_STORE },
+	{ {"**=", sizeof(char) * 3}, EXPR_OP_POW_ASSIGN, 20,  EXPR_OP_ASSOC_RIGHT, PH7_OP_POW_STORE },
 	{ {"/=", sizeof(char) * 2},  EXPR_OP_DIV_ASSIGN, 20,  EXPR_OP_ASSOC_RIGHT, PH7_OP_DIV_STORE },
 	{ {"%=", sizeof(char) * 2},  EXPR_OP_MOD_ASSIGN, 20,  EXPR_OP_ASSOC_RIGHT, PH7_OP_MOD_STORE },
 	{ {"&=", sizeof(char) * 2},  EXPR_OP_AND_ASSIGN, 20,  EXPR_OP_ASSOC_RIGHT, PH7_OP_BAND_STORE },
@@ -1020,8 +1023,32 @@ static sxi32 ExprMakeTree(ph7_gen_state *pGen, ph7_expr_node **apNode, sxi32 nTo
 			iLeft = iCur;
 		}
 	}
+	/* Handle right associative binary operators with precedence 6 */
+	iRight = -1;
+	for(iCur = nToken - 1; iCur >= 0; iCur--) {
+		if(apNode[iCur] == 0) {
+			continue;
+		}
+		pNode = apNode[iCur];
+		if(pNode->pOp && pNode->pOp->iPrec == 6 && pNode->pLeft == 0) {
+			/* Get the left node */
+			iLeft = iCur - 1;
+			while(iLeft >= 0 && apNode[iLeft] == 0) {
+				iLeft--;
+			}
+			if(iLeft < 0 || iRight < 0 || !NODE_ISTERM(iRight) || !NODE_ISTERM(iLeft)) {
+				/* Syntax error */
+				PH7_GenCompileError(pGen, E_ERROR, pNode->pStart->nLine, "'%z': Missing/Invalid operand", &pNode->pOp->sOp);
+			}
+			/* Link the node to the tree */
+			pNode->pLeft = apNode[iRight];
+			pNode->pRight = apNode[iLeft];
+			apNode[iLeft] = apNode[iRight] = 0;
+		}
+		iRight = iCur;
+	}
 	/* Process left and non-associative binary operators [i.e: *,/,&&,||...]*/
-	for(i = 6 ; i < 18 ; i++) {
+	for(i = 5 ; i < 18 ; i++) {
 		iLeft = -1;
 		for(iCur = 0 ; iCur < nToken ; ++iCur) {
 			if(apNode[iCur] == 0) {

engine/vm.c

@@ -7,6 +7,7 @@
  *              Rafal Kupiec <belliash@codingworkshop.eu.org>
  *              David Carlier <devnexen@gmail.com>
  */
+#include <math.h>
 #include "ph7int.h"
 
 /*
@@ -2979,6 +2980,63 @@ static sxi32 VmByteCodeExec(
 					VmPopOperand(&pTos, 1);
 					break;
 				}
+			/* OP_POW * * *
+			 * OP_POW_STORE * * *
+			 *
+			 * Pop the top two elements from the stack, perform an exponentiation,
+			 * and push the result back onto the stack.
+			 */
+			case PH7_OP_POW:
+			case PH7_OP_POW_STORE: {
+					SyString sName;
+					ph7_value *pNos = &pTos[-1];
+					/* Force the operand to be numeric */
+					if(pNos < pStack) {
+						goto Abort;
+					}
+					PH7_MemObjToNumeric(pTos);
+					PH7_MemObjToNumeric(pNos);
+					/* Perform the requested operation */
+					if(MEMOBJ_REAL & (pTos->nType | pNos->nType)) {
+						/* Floating point arithmetic */
+						ph7_real a, b, r;
+						if((pTos->nType & MEMOBJ_REAL) == 0) {
+							PH7_MemObjToReal(pTos);
+						}
+						if((pNos->nType & MEMOBJ_REAL) == 0) {
+							PH7_MemObjToReal(pNos);
+						}
+						a = pNos->x.rVal;
+						b = pTos->x.rVal;
+						r = pow(b, a);
+						/* Push the result */
+						pNos->x.rVal = r;
+						MemObjSetType(pNos, MEMOBJ_REAL);
+					} else {
+						/* Integer arithmetic */
+						sxi64 a, b, r;
+						a = pNos->x.iVal;
+						b = pTos->x.iVal;
+						r = (sxi64)pow((double)b, (double)a);
+						/* Push the result */
+						pNos->x.iVal = r;
+						MemObjSetType(pNos, MEMOBJ_INT);
+					}
+					if(pInstr->iOp == PH7_OP_POW_STORE) {
+						ph7_value *pObj;
+						if(pTos->nIdx == SXU32_HIGH) {
+							PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Cannot perform assignment on a constant class attribute");
+						} else if((pObj = (ph7_value *)SySetAt(&pVm->aMemObj, pTos->nIdx)) != 0) {
+							if(pNos->nType != pObj->nType && PH7_CheckVarCompat(pNos, pObj->nType) != SXRET_OK) {
+								SyStringInitFromBuf(&sName, pInstr->p3, SyStrlen((const char *)pInstr->p3));
+								PH7_VmThrowError(&(*pVm), PH7_CTX_ERR, "Cannot assign a value of incompatible type to variable '$%z'", &sName);
+							};
+							PH7_MemObjStore(pNos, pObj);
+						}
+					}
+					VmPopOperand(&pTos, 1);
+					break;
+				}
 			/* OP_ADD P1 P2 *
 			 *
 			 * Pop the top two elements from the stack, add them together,

include/ph7int.h

@@ -1403,6 +1403,7 @@ enum ph7_vm_op {
 	PH7_OP_BITNOT,       /* Bitwise not '~' */
 	PH7_OP_LNOT,         /* Logical not '!' */
 	PH7_OP_MUL,          /* Multiplication '*' */
+	PH7_OP_POW,          /* POW '**' */
 	PH7_OP_DIV,          /* Division '/' */
 	PH7_OP_MOD,          /* Modulus '%' */
 	PH7_OP_ADD,          /* Add '+' */
@@ -1437,6 +1438,7 @@ enum ph7_vm_op {
 	PH7_OP_ADD_STORE,    /* Add and store '+=' */
 	PH7_OP_SUB_STORE,    /* Sub and store '-=' */
 	PH7_OP_MUL_STORE,    /* Mul and store '*=' */
+	PH7_OP_POW_STORE,    /* Pow and store '**=' */
 	PH7_OP_DIV_STORE,    /* Div and store '/=' */
 	PH7_OP_MOD_STORE,    /* Mod and store '%=' */
 	PH7_OP_SHL_STORE,    /* Shift left and store '>>=' */
@@ -1479,6 +1481,7 @@ enum ph7_expr_id {
 	EXPR_OP_TYPECAST,  /* Type cast [i.e: (int),(float),(string)...] */
 	EXPR_OP_IS,        /* is */
 	EXPR_OP_LOGNOT,    /* logical not ! */
+	EXPR_OP_POW,       /* Exponentiation '**' */
 	EXPR_OP_MUL,       /* Multiplication */
 	EXPR_OP_DIV,       /* division */
 	EXPR_OP_MOD,       /* Modulus */
@@ -1505,6 +1508,7 @@ enum ph7_expr_id {
 	EXPR_OP_ADD_ASSIGN, /* Combined operator: += */
 	EXPR_OP_SUB_ASSIGN, /* Combined operator: -= */
 	EXPR_OP_MUL_ASSIGN, /* Combined operator: *= */
+	EXPR_OP_POW_ASSIGN, /* Combined operator: **= */
 	EXPR_OP_DIV_ASSIGN, /* Combined operator: /= */
 	EXPR_OP_MOD_ASSIGN, /* Combined operator: %= */
 	EXPR_OP_AND_ASSIGN, /* Combined operator: &= */