From 84f78956841214437e2be94fd6225895e66dce0e Mon Sep 17 00:00:00 2001
From: CPunch <sethtstubbs@gmail.com>
Date: Fri, 1 Jan 2021 00:47:15 -0600
Subject: [PATCH] Added modulo operator '%'

- added OP_MOD, which performs a modulo operation on the 2 <number> values on the stack. Pops the 2 values and pushes the result.
- also added TOKEN_PERCENT to the lexer, and extended binary() in cparse.c to support it.
---
 Makefile         |  2 +-
 src/cdebug.c     |  2 ++
 src/clex.c       |  1 +
 src/clex.h       |  1 +
 src/coperators.h |  1 +
 src/cparse.c     |  2 ++
 src/cvm.c        | 14 ++++++++++++++
 7 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 7a995df..90f9d79 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@
 
 CC=clang
 CFLAGS=-fPIE -Wall -O3 -std=c11
-LDFLAGS=#-fsanitize=address
+LDFLAGS=-lm #-fsanitize=address
 OUT=bin/cosmo
 
 CHDR=\
diff --git a/src/cdebug.c b/src/cdebug.c
index 37bc680..97cc066 100644
--- a/src/cdebug.c
+++ b/src/cdebug.c
@@ -144,6 +144,8 @@ int disasmInstr(CChunk *chunk, int offset, int indent) {
             return simpleInstruction("OP_MULT", offset);
         case OP_DIV:
             return simpleInstruction("OP_DIV", offset);
+        case OP_MOD:
+            return simpleInstruction("OP_MOD", offset);
         case OP_TRUE:
             return simpleInstruction("OP_TRUE", offset);
         case OP_FALSE:
diff --git a/src/clex.c b/src/clex.c
index fdaaa33..ad063b8 100644
--- a/src/clex.c
+++ b/src/clex.c
@@ -308,6 +308,7 @@ CToken cosmoL_scanToken(CLexState *state) {
         case ',': return makeToken(state, TOKEN_COMMA);
         case ':': return makeToken(state, TOKEN_COLON);
         case '*': return makeToken(state, TOKEN_STAR);
+        case '%': return makeToken(state, TOKEN_PERCENT);
         case '#': return makeToken(state, TOKEN_POUND);
         case '/': return makeToken(state, TOKEN_SLASH);
         // two character tokens
diff --git a/src/clex.h b/src/clex.h
index 7f020a6..67fe084 100644
--- a/src/clex.h
+++ b/src/clex.h
@@ -23,6 +23,7 @@ typedef enum {
     TOKEN_SLASH,
     TOKEN_STAR,
     TOKEN_POUND,
+    TOKEN_PERCENT,
     TOKEN_EOS, // end of statement
 
     // equality operators
diff --git a/src/coperators.h b/src/coperators.h
index 2280549..a1f0603 100644
--- a/src/coperators.h
+++ b/src/coperators.h
@@ -37,6 +37,7 @@ typedef enum {
     OP_SUB,
     OP_MULT,
     OP_DIV,
+    OP_MOD,
     OP_NOT,
     OP_NEGATE,
     OP_COUNT,
diff --git a/src/cparse.c b/src/cparse.c
index 512797a..f6163d6 100644
--- a/src/cparse.c
+++ b/src/cparse.c
@@ -430,6 +430,7 @@ static void binary(CParseState *pstate, bool canAssign) {
         case TOKEN_MINUS:   writeu8Chunk(pstate->state, getChunk(pstate), OP_SUB, cachedLine); break;
         case TOKEN_STAR:    writeu8Chunk(pstate->state, getChunk(pstate), OP_MULT, cachedLine); break;
         case TOKEN_SLASH:   writeu8Chunk(pstate->state, getChunk(pstate), OP_DIV, cachedLine); break;
+        case TOKEN_PERCENT: writeu8Chunk(pstate->state, getChunk(pstate), OP_MOD, cachedLine); break;
         // EQUALITY
         case TOKEN_EQUAL_EQUAL:     writeu8Chunk(pstate->state, getChunk(pstate), OP_EQUAL, cachedLine); break;
         case TOKEN_GREATER:         writeu8Chunk(pstate->state, getChunk(pstate), OP_GREATER, cachedLine); break;
@@ -730,6 +731,7 @@ ParseRule ruleTable[] = {
     [TOKEN_PLUS_PLUS]       = {preincrement, NULL, PREC_TERM},
     [TOKEN_SLASH]           = {NULL, binary, PREC_FACTOR},
     [TOKEN_STAR]            = {NULL, binary, PREC_FACTOR},
+    [TOKEN_PERCENT]         = {NULL, binary, PREC_FACTOR},
     [TOKEN_POUND]           = {unary, NULL, PREC_NONE},
     [TOKEN_EOS]             = {NULL, NULL, PREC_NONE},
     [TOKEN_BANG]            = {unary, NULL, PREC_NONE},
diff --git a/src/cvm.c b/src/cvm.c
index 3fad491..915dc61 100644
--- a/src/cvm.c
+++ b/src/cvm.c
@@ -6,6 +6,8 @@
 #include <stdarg.h>
 #include <string.h>
 
+#include <math.h>
+
 COSMO_API void cosmoV_pushFString(CState *state, const char *format, ...) {
     va_list args;
     va_start(args, format);
@@ -802,6 +804,18 @@ int cosmoV_execute(CState *state) {
                 NUMBEROP(cosmoV_newNumber, /)
                 break;
             }
+            case OP_MOD: {
+                StkPtr valA = cosmoV_getTop(state, 1);
+                StkPtr valB = cosmoV_getTop(state, 0);
+                if (IS_NUMBER(*valA) && IS_NUMBER(*valB)) {
+                    cosmoV_setTop(state, 2); /* pop the 2 values */
+                    cosmoV_pushValue(state, cosmoV_newNumber(fmod(cosmoV_readNumber(*valA), cosmoV_readNumber(*valB))));
+                } else { \
+                    cosmoV_error(state, "Expected numbers, got %s and %s!", cosmoV_typeStr(*valA), cosmoV_typeStr(*valB));
+                    return -1; \
+                } \
+                break;
+            }
             case OP_NOT: {
                 cosmoV_pushBoolean(state, isFalsey(cosmoV_pop(state)));
                 break;