Add more code

Add some funcitons to work with variables, add more instructions and add
ability to stop the code from `ccl_instruction`

7 files changed, 85 insertions, 4 deletions

diff --git a/src/instruction/add.c b/src/instruction/add.c
new file mode 100644
index 0000000..81bef71
--- /dev/null
+++ b/src/instruction/add.c
@@ -0,0 +1,14 @@
+#include "3cl.h"
+
+#include "readchar.h"
+#include "stack.h"
+#include "utils.h"
+
+struct CCLFrame *ccl_instruction_add(struct CCL *ccl, struct CCLFrame *frame)
+{
+    if (ccl->stack.cur < 2)
+        die(1, "stack size is %d (%d required)", ccl->stack.cur, 2);
+    ccl_stack_push(&ccl->stack, ccl_stack_pop(&ccl->stack) + ccl_stack_pop(&ccl->stack));
+
+    return frame;
+}
diff --git a/src/instruction/decrement.c b/src/instruction/decrement.c
index f7f54dd..ce3af87 100644
--- a/src/instruction/decrement.c
+++ b/src/instruction/decrement.c
@@ -1,8 +1,11 @@
 #include "3cl.h"
-#include "instruction.h"
+
+#include "utils.h"
 
 struct CCLFrame *ccl_instruction_decrement(struct CCL *ccl, struct CCLFrame *frame)
 {
+    if (ccl->stack.cur < 1)
+        die(1, "stack size is %d (%d required)", ccl->stack.cur, 1);
     --ccl->stack.stack[ccl->stack.cur];
     return frame;
 }
diff --git a/src/instruction/increment.c b/src/instruction/increment.c
index 51697f1..d2d51a5 100644
--- a/src/instruction/increment.c
+++ b/src/instruction/increment.c
@@ -1,8 +1,11 @@
 #include "3cl.h"
-#include "instruction.h"
+
+#include "utils.h"
 
 struct CCLFrame *ccl_instruction_increment(struct CCL *ccl, struct CCLFrame *frame)
 {
+    if (ccl->stack.cur < 1)
+        die(1, "stack size is %d (%d required)", ccl->stack.cur, 1);
     ++ccl->stack.stack[ccl->stack.cur];
     return frame;
 }
diff --git a/src/instruction/nop.c b/src/instruction/nop.c
index 8e05396..778b8ed 100644
--- a/src/instruction/nop.c
+++ b/src/instruction/nop.c
@@ -1,5 +1,4 @@
 #include "3cl.h"
-#include "instruction.h"
 
 struct CCLFrame *ccl_instruction_nop(struct CCL *ccl, struct CCLFrame *frame)
 {
diff --git a/src/instruction/pushzero.c b/src/instruction/pushzero.c
index ef380cd..cd0a023 100644
--- a/src/instruction/pushzero.c
+++ b/src/instruction/pushzero.c
@@ -1,5 +1,4 @@
 #include "3cl.h"
-#include "instruction.h"
 
 #include "stack.h"
 
diff --git a/src/instruction/reverse.c b/src/instruction/reverse.c
new file mode 100644
index 0000000..bd863ae
--- /dev/null
+++ b/src/instruction/reverse.c
@@ -0,0 +1,51 @@
+#include "3cl.h"
+
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "readchar.h"
+#include "utils.h"
+#include "variable.h"
+
+
+struct CCLFrame *ccl_instruction_reverse(struct CCL *ccl, struct CCLFrame *frame)
+{
+    char varname;
+    size_t toreverse;
+
+    varname = ccl_readchar(ccl, frame, CCL_RC_CCL_VARUS);
+    if (varname == '\0')
+    {
+        die(1, "Unexpected EOF");
+    } else if (varname == '_')
+    {
+        toreverse = ccl->stack.cur;
+    } else
+    {
+        struct CCLVariable *var = ccl_variable_getany(ccl, frame, varname);
+        if (var == NULL)
+            die(1, "Unknown variable '%c' at %d", varname, frame->ep);
+        toreverse = var->value;
+    }
+
+    if (ccl->stack.cur < toreverse)
+        die(1, "stack size is %d (%d required)", ccl->stack.cur, toreverse);
+
+    CCLNum *temp = malloc(sizeof(*temp) * toreverse);
+    if (temp == NULL)
+        die(1, "malloc(): %s", strerror(errno));
+
+    size_t start;
+    for (start = 0; start < toreverse; ++start)
+        temp[start] = ccl->stack.stack[ccl->stack.cur - start];
+    start = ccl->stack.cur - start;
+    for (int i = 0; i < toreverse; ++i)
+        ccl->stack.stack[start + i] = temp[i];
+
+    free(temp);
+
+    return frame;
+}
diff --git a/src/instruction/subtract.c b/src/instruction/subtract.c
new file mode 100644
index 0000000..f140cfb
--- /dev/null
+++ b/src/instruction/subtract.c
@@ -0,0 +1,12 @@
+#include "3cl.h"
+
+#include "stack.h"
+#include "utils.h"
+
+struct CCLFrame *ccl_instruction_subtract(struct CCL *ccl, struct CCLFrame *frame)
+{
+    if (ccl->stack.cur < 2)
+        die(1, "stack size is %d (%d required)", ccl->stack.cur, 2);
+    ccl_stack_push(&ccl->stack, -ccl_stack_pop(&ccl->stack) + ccl_stack_pop(&ccl->stack));
+    return frame;
+}