feat: variables and shi

1 files changed, 107 insertions, 33 deletions

diff --git a/eval.c b/eval.c
index b0ad454..fc6e6d7 100644
--- a/eval.c
+++ b/eval.c
@@ -2,12 +2,47 @@
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stdio.h>
+#include <string.h>
 
 #include "eval.h"
 
-static int evaluate_type(const struct Node* node, struct Type* out);
-static int evaluate_value(const struct Node* node, int64_t* out);
-static int evaluate_condition(const struct Node* node, bool* out);
+static int evaluate_type(struct Machine* machine, const struct Node* node, struct Type* out);
+static int evaluate_value(struct Machine* machine, const struct Node* node, int64_t* out);
+static int evaluate_condition(struct Machine* machine, const struct Node* node, bool* out);
+
+void machine_init(struct Machine* machine)
+{
+    memset(machine, 0, sizeof *machine);
+}
+
+static struct Variable* find_variable(struct Machine* machine, const char* name)
+{
+    for (size_t index = 0; index < VARIABLES_MAX; index++)
+    {
+        struct Variable* variable = &machine->variables[index];
+        if (variable->declared && strcmp(variable->name, name) == 0)
+            return variable;
+    }
+
+    return NULL;
+}
+
+static bool bind_variable(struct Machine* machine, const char* name, int64_t value)
+{
+    for (size_t index = 0; index < VARIABLES_MAX; index++)
+    {
+        struct Variable* variable = &machine->variables[index];
+        if (variable->declared)
+            continue;
+
+        (void)snprintf(variable->name, sizeof variable->name, "%s", name);
+        variable->value = value;
+        variable->declared = true;
+        return true;
+    }
+
+    return false;
+}
 
 static int complain(const struct Node* node, const char* message)
 {
@@ -15,19 +50,21 @@ static int complain(const struct Node* node, const char* message)
     return 1;
 }
 
-static int evaluate_operands(const struct Node* node, int64_t* left, int64_t* right)
+static int evaluate_operands(struct Machine* machine, const struct Node* node, int64_t* left,
+                             int64_t* right)
 {
-    if (evaluate_value(node->first, left))
+    if (evaluate_value(machine, node->first, left))
         return 1;
 
-    return evaluate_value(node->second, right);
+    return evaluate_value(machine, node->second, right);
 }
 
-static int evaluate_value(const struct Node* node, int64_t* out)
+static int evaluate_value(struct Machine* machine, const struct Node* node, int64_t* out)
 {
     int64_t left = 0;
     int64_t right = 0;
     struct Type type;
+    struct Variable* variable = NULL;
     bool truth = false;
     switch (node->kind)
     {
@@ -35,19 +72,19 @@ static int evaluate_value(const struct Node* node, int64_t* out)
             *out = (int64_t)node->first->character - (int64_t)node->second->character;
             return 0;
         case VALUE_SUM:
-            if (evaluate_operands(node, &left, &right))
+            if (evaluate_operands(machine, node, &left, &right))
                 return 1;
 
             *out = left + right;
             return 0;
         case VALUE_PRODUCT:
-            if (evaluate_operands(node, &left, &right))
+            if (evaluate_operands(machine, node, &left, &right))
                 return 1;
 
             *out = left * right;
             return 0;
         case VALUE_QUOTIENT:
-            if (evaluate_operands(node, &left, &right))
+            if (evaluate_operands(machine, node, &left, &right))
                 return 1;
 
             if (right == 0)
@@ -57,16 +94,23 @@ static int evaluate_value(const struct Node* node, int64_t* out)
             return 0;
         case VALUE_EXTENT:
         case VALUE_TUPLE_SIZE:
-            if (evaluate_type(node->first, &type))
+            if (evaluate_type(machine, node->first, &type))
                 return 1;
             *out = type.kind == KIND_ARRAY ? type.number : 0;
             return 0;
-        case VALUE_INTEGRAL_CONSTANT: return evaluate_value(node->first, out);
+        case VALUE_INTEGRAL_CONSTANT: return evaluate_value(machine, node->first, out);
+        case VALUE_VARIABLE:
+            variable = find_variable(machine, node->name);
+            if (variable == NULL)
+                return complain(node, "that name was never declared");
+
+            *out = variable->value;
+            return 0;
         case VALUE_CONDITIONAL:
-            if (evaluate_condition(node->first, &truth))
+            if (evaluate_condition(machine, node->first, &truth))
                 return 1;
 
-            return evaluate_value(truth ? node->second : node->third, out);
+            return evaluate_value(machine, truth ? node->second : node->third, out);
         default: break;
     }
 
@@ -74,7 +118,7 @@ static int evaluate_value(const struct Node* node, int64_t* out)
     return 1;
 }
 
-static int evaluate_type(const struct Node* node, struct Type* out)
+static int evaluate_type(struct Machine* machine, const struct Node* node, struct Type* out)
 {
     out->kind = KIND_VOID;
     out->number = 0;
@@ -86,18 +130,19 @@ static int evaluate_type(const struct Node* node, struct Type* out)
         case TYPE_INT32: out->kind = KIND_INT32; return 0;
         case TYPE_BYTE: out->kind = KIND_BYTE; return 0;
         case TYPE_SIZE: out->kind = KIND_SIZE; return 0;
-        case TYPE_REMOVE_CV: return evaluate_type(node->first, out);
+        case TYPE_REMOVE_CV: return evaluate_type(machine, node->first, out);
         case TYPE_ARRAY:
-            if (evaluate_type(node->first, &element) || evaluate_value(node->second, &out->number))
+            if (evaluate_type(machine, node->first, &element) ||
+                evaluate_value(machine, node->second, &out->number))
                 return 1;
             out->kind = KIND_ARRAY;
             return 0;
         case TYPE_CONDITIONAL:
-            if (evaluate_condition(node->first, &truth))
+            if (evaluate_condition(machine, node->first, &truth))
                 return 1;
-            return evaluate_type(truth ? node->second : node->third, out);
+            return evaluate_type(machine, truth ? node->second : node->third, out);
         case TYPE_DECLTYPE:
-            if (evaluate_value(node->first, &out->number))
+            if (evaluate_value(machine, node->first, &out->number))
                 return 1;
             out->kind = KIND_VALUE;
             return 0;
@@ -113,7 +158,7 @@ static bool same_type(const struct Type* left, const struct Type* right)
     return left->kind == right->kind && left->number == right->number;
 }
 
-static int evaluate_condition(const struct Node* node, bool* out)
+static int evaluate_condition(struct Machine* machine, const struct Node* node, bool* out)
 {
     int64_t left = 0;
     int64_t right = 0;
@@ -125,19 +170,20 @@ static int evaluate_condition(const struct Node* node, bool* out)
         case COND_TRUE: *out = true; return 0;
         case COND_FALSE: return 0;
         case COND_IS_SAME:
-            if (evaluate_type(node->first, &left_type) || evaluate_type(node->second, &right_type))
+            if (evaluate_type(machine, node->first, &left_type) ||
+                evaluate_type(machine, node->second, &right_type))
                 return 1;
 
             *out = same_type(&left_type, &right_type);
             return 0;
         case COND_EQUAL:
-            if (evaluate_operands(node, &left, &right))
+            if (evaluate_operands(machine, node, &left, &right))
                 return 1;
 
             *out = left == right;
             return 0;
         case COND_LESS:
-            if (evaluate_operands(node, &left, &right))
+            if (evaluate_operands(machine, node, &left, &right))
                 return 1;
 
             *out = left < right;
@@ -149,10 +195,37 @@ static int evaluate_condition(const struct Node* node, bool* out)
     return 1;
 }
 
-static enum RunStatus emit(const struct Node* node)
+static enum RunStatus declare(struct Machine* machine, const struct Node* node)
+{
+    if (find_variable(machine, node->name) != NULL)
+    {
+        (void)complain(node, "already declared, and there is no changing that");
+        return RUN_FAILED;
+    }
+
+    struct Type type;
+    if (evaluate_type(machine, node->first, &type))
+        return RUN_FAILED;
+
+    if (type.kind != KIND_VALUE)
+    {
+        (void)complain(node, "that type carries no value, decltype something");
+        return RUN_FAILED;
+    }
+
+    if (!bind_variable(machine, node->name, type.number))
+    {
+        (void)complain(node, "too many variables, this was never meant to scale");
+        return RUN_FAILED;
+    }
+
+    return RUN_DONE;
+}
+
+static enum RunStatus emit(struct Machine* machine, const struct Node* node)
 {
     struct Type type;
-    if (evaluate_type(node->first, &type))
+    if (evaluate_type(machine, node->first, &type))
         return RUN_FAILED;
 
     switch (type.kind)
@@ -168,10 +241,10 @@ static enum RunStatus emit(const struct Node* node)
     return RUN_DONE;
 }
 
-static enum RunStatus static_assert_statement(const struct Node* node)
+static enum RunStatus static_assert_statement(struct Machine* machine, const struct Node* node)
 {
     bool truth = false;
-    if (evaluate_condition(node->first, &truth))
+    if (evaluate_condition(machine, node->first, &truth))
         return RUN_FAILED;
 
     if (!truth)
@@ -183,12 +256,13 @@ static enum RunStatus static_assert_statement(const struct Node* node)
     return RUN_DONE;
 }
 
-static enum RunStatus execute_one(const struct Node* node)
+static enum RunStatus execute_one(struct Machine* machine, const struct Node* node)
 {
     switch (node->kind)
     {
-        case STMT_EMIT: return emit(node);
-        case STMT_STATIC_ASSERT: return static_assert_statement(node);
+        case STMT_DECLARE: return declare(machine, node);
+        case STMT_EMIT: return emit(machine, node);
+        case STMT_STATIC_ASSERT: return static_assert_statement(machine, node);
         default: break;
     }
 
@@ -196,11 +270,11 @@ static enum RunStatus execute_one(const struct Node* node)
     return RUN_FAILED;
 }
 
-enum RunStatus execute(const struct Node* statement)
+enum RunStatus execute(struct Machine* machine, const struct Node* statement)
 {
     while (statement != NULL)
     {
-        enum RunStatus status = execute_one(statement);
+        enum RunStatus status = execute_one(machine, statement);
         if (status != RUN_DONE)
             return status;