diff --git a/build.sh b/build.sh
index 82b6038..1f26cea 100755
--- a/build.sh
+++ b/build.sh
@@ -73,6 +73,8 @@ gcc tests/src/test-objects.c -o build/test-objects $FLAGS -Lbuild/ -lnoja-object
 
 gcc src/main.c \
 	src/debug.c \
+	src/eval.c \
+	src/buildvalue.c \
 	src/heap_reconst.c \
 	temp/o_builtins.o \
 	temp/o_net_builtins.o \
diff --git a/src/buildvalue.c b/src/buildvalue.c
new file mode 100644
index 0000000..dff09b7
--- /dev/null
+++ b/src/buildvalue.c
@@ -0,0 +1,294 @@
+#include <ctype.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include "buildvalue.h"
+#include "eval.h"
+
+static Object *walkValue(const char *fmt, int *i, va_list va, Heap *heap, Error *error);
+
+static Object *walkMapValue(const char *fmt, int *i, va_list va, Heap *heap, Error *error)
+{
+	assert(fmt[*i] == '{');
+
+	*i += 1; // Skip the '{'.
+
+	while(isspace(fmt[*i]))
+		*i += 1;
+
+	Object *map = Object_NewMap(-1, heap, error);
+
+	if(map == NULL)
+		return NULL;
+
+	if(fmt[*i] != '}')
+		while(1)
+			{
+				Object *key = walkValue(fmt, i, va, heap, error);
+
+				if(key == NULL)
+					return NULL;
+
+				while(isspace(fmt[*i]))
+					*i += 1;
+
+				if(fmt[*i] == '\0')
+					{
+						Error_Report(error, 0, "Format ended inside a map expression");
+						return NULL;
+					}
+
+				if(fmt[*i] != ':')
+					{
+						Error_Report(error, 0, "Got unexpected '%c' in format where ':' was expected", fmt[*i]);
+						return NULL;
+					}
+
+				*i += 1; // Skip the ':'.
+
+				Object *val = walkValue(fmt, i, va, heap, error);
+
+				if(val == NULL)
+					return NULL;
+
+				if(!Object_Insert(map, key, val, heap, error))
+					return NULL;
+
+				while(isspace(fmt[*i]))
+					*i += 1;
+
+				if(fmt[*i] == '\0')
+					{
+						Error_Report(error, 0, "Format ended inside a map expression");
+						return NULL;
+					}
+
+				if(fmt[*i] == '}')
+					break;
+
+				if(fmt[*i] != ',')
+					{
+						Error_Report(error, 0, "Got unexpected '%c' in format where either ',' or '}' were expected", fmt[*i]);
+						return NULL;
+					}
+
+				*i += 1; // Skip the ','.
+			}
+
+	assert(fmt[*i] == '}');
+
+	*i += 1; // Skip the '}'.
+	
+	return map;
+}
+static Object *walkListValue(const char *fmt, int *i, va_list va, Heap *heap, Error *error)
+{
+	assert(fmt[*i] == '[');
+
+	*i += 1; // Skip the '['.
+
+	while(isspace(fmt[*i]))
+		*i += 1;
+
+	Object *maybe[8], **ptrs = maybe;
+	int ptrs_cap = sizeof(maybe) / sizeof(maybe[0]), 
+		ptrs_num = 0;
+
+	if(fmt[*i] != ']')
+		while(1)
+			{
+				Object *item = walkValue(fmt, i, va, heap, error);
+
+				if(item == NULL)
+					{
+						if(ptrs != maybe) free(ptrs);
+						return NULL;
+					}
+
+				if(ptrs_cap == ptrs_num)
+					{
+						int new_capacity = ptrs_cap * 2;
+						
+						Object **temp;
+
+						if(ptrs == maybe)
+							{
+								temp = malloc(sizeof(Object*) * new_capacity);
+								
+								if(temp != NULL)
+									memcpy(temp, ptrs, ptrs_num * sizeof(Object*));	
+							}
+						else
+							temp = realloc(ptrs, sizeof(Object*) * new_capacity);
+
+						if(temp == NULL)
+							{
+								Error_Report(error, 1, "Insufficient memory");
+								if(ptrs != maybe) free(ptrs);
+								return NULL;
+							}
+
+						ptrs = temp;
+						ptrs_cap = new_capacity;
+					}
+
+				ptrs[ptrs_num++] = item;
+
+				while(isspace(fmt[*i]))
+					*i += 1;
+
+				if(fmt[*i] == '\0')
+					{
+						Error_Report(error, 0, "Format ended inside a list expression");
+						if(ptrs != maybe) free(ptrs);
+						return NULL;
+					}
+
+				if(fmt[*i] == ']')
+					break;
+
+				if(fmt[*i] != ',')
+					{
+						Error_Report(error, 0, "Got unexpected '%c' in format where either ',' or ']' were expected", fmt[*i]);
+						if(ptrs != maybe) free(ptrs);
+						return NULL;
+					}
+
+				*i += 1; // Skip the ','.
+			}
+
+	assert(fmt[*i] == ']');
+
+	*i += 1; // Skip the ']'.
+
+	Object *list = Object_NewList2(ptrs_num, ptrs, heap, error);
+
+	if(ptrs != maybe) 
+		free(ptrs);
+	
+	return list;
+}
+
+static Object *walkValue(const char *fmt, int *i, va_list va, Heap *heap, Error *error)
+{
+	int i_;
+	if(i == NULL)
+		i = &i_;
+
+	while(isspace(fmt[*i]))
+		*i += 1;
+
+	if(fmt[*i] == '\0')
+		{
+			Error_Report(error, 0, "Empty format");
+			return NULL;
+		}
+
+	if(fmt[*i] == '{')
+		return walkMapValue(fmt, i, va, heap, error);
+
+	if(fmt[*i] == '[')
+		return walkListValue(fmt, i, va, heap, error);
+
+	if(fmt[*i] != '$')
+		{
+			Error_Report(error, 0, "Unexpected character '%c' in format", fmt[*i]);
+			return NULL;
+		}
+
+	assert(fmt[*i] == '$');
+
+	*i += 1;
+
+	Object *o;
+
+	switch(fmt[*i])
+		{
+			case '\0':
+			Error_Report(error, 0, "Format ended after '$'");
+			return NULL;
+		
+			case '{':
+			{
+				// Noja expression until the closing '}'.
+				
+				*i += 1; // Skip the '{'.
+
+				int start = *i;
+
+				while(fmt[*i] != '\0' && fmt[*i] != '}') // TODO: Escape '}'.
+					*i += 1;
+
+				if(fmt[*i] == '\0')
+					{
+						// ERROR: Format ended inside of ${..}.
+						return NULL;
+					}
+
+				int end = fmt[*i];
+
+				// NOTE: The last '}' is skipped after the switch.
+				
+				const char *src = fmt + start;
+				int         len = end - start;
+					
+				o = eval(src, len, NULL, heap, error);
+
+				if(o == NULL)
+					return NULL;
+				break;
+			}
+
+			case 'i':
+			o = Object_FromInt(va_arg(va, long long int), heap, error);
+			if(o == NULL) return NULL;
+			break;
+
+			case 'f':
+			o = Object_FromFloat(va_arg(va, double), heap, error);
+			if(o == NULL) return NULL;
+			break;
+
+			case 'b':
+			// NOTE: Actually we want a _Bool, not an int.
+			//       But gcc says:
+			//       > warning: ‘_Bool’ is promoted to ‘int’ when passed through ‘...’
+			//       > [...]
+			//       > (so you should pass ‘int’ not ‘_Bool’ to ‘va_arg’)
+			//
+			o = Object_FromBool(va_arg(va, int), heap, error);
+			if(o == NULL) return NULL;
+			break;
+
+			case 's':
+			o = Object_FromString(va_arg(va, char*), -1, heap, error);
+			if(o == NULL) return NULL;
+			break;
+
+			case 'o':
+			o = va_arg(va, Object*);
+			assert(o != NULL);
+			break;
+
+			default:
+			Error_Report(error, 0, "Invalid format specifier '%c'", fmt[*i]);
+			return NULL;
+		}
+
+	*i += 1;
+	return o;
+}
+
+Object *buildValue2(Heap *heap, Error *error, const char *fmt, va_list va)
+{
+	return walkValue(fmt, NULL, va, heap, error);
+}
+
+Object *buildValue(Heap *heap, Error *error, const char *fmt, ...)
+{
+	va_list va;
+	va_start(va, fmt);
+	Object *o = buildValue2(heap, error, fmt, va);
+	va_end(va);
+	return o;
+}
\ No newline at end of file
diff --git a/src/buildvalue.h b/src/buildvalue.h
new file mode 100644
index 0000000..e8b5461
--- /dev/null
+++ b/src/buildvalue.h
@@ -0,0 +1,6 @@
+#include <stdarg.h>
+#include "utils/error.h"
+#include "objects/objects.h"
+
+Object *buildValue2(Heap *heap, Error *error, const char *fmt, va_list va);
+Object *buildValue(Heap *heap, Error *error, const char *fmt, ...);
\ No newline at end of file
diff --git a/src/eval.c b/src/eval.c
new file mode 100644
index 0000000..213c11c
--- /dev/null
+++ b/src/eval.c
@@ -0,0 +1,75 @@
+#include "compiler/parse.h"
+#include "compiler/compile.h"
+#include "runtime/runtime.h"
+#include "o_builtins.h"
+#include "eval.h"
+
+Object *eval(const char *str, int len, Object *closure, Heap *heap, Error *error)
+{
+	Source *s = Source_FromString(NULL, str, len, error);
+
+	if(s == NULL)
+		return NULL; // Propagate.
+
+	BPAlloc *alloc = BPAlloc_Init(-1);
+
+	if(alloc == NULL)
+		{
+			Error_Report(error, 1, "Insufficient memory");
+			return NULL;
+		}
+
+	AST *ast = parse(s, alloc, error);
+
+	if(ast == NULL)
+		{
+			BPAlloc_Free(alloc);
+			Source_Free(s);
+			return NULL;
+		}
+
+	Executable *exe = compile(ast, alloc, error);
+
+	if(exe == NULL)
+		{
+			BPAlloc_Free(alloc);
+			Source_Free(s);
+			return NULL;
+		}
+
+	BPAlloc_Free(alloc);
+	Source_Free(s);
+
+	Runtime *runt = Runtime_New2(-1, heap, 0, NULL, NULL);
+
+	if(runt == NULL)
+		{
+			Error_Report(error, 1, "Insufficient memory");
+			Executable_Free(exe);
+			return NULL;
+		}
+
+	Object *bins = Object_NewBuiltinsMap(runt, heap, error);
+
+	if(bins == NULL)
+		{
+			Runtime_Free(runt);
+			Executable_Free(exe);
+			return NULL;
+		}
+
+	Runtime_SetBuiltins(runt, bins);
+
+	Object *o = run(runt, error, exe, 0, closure, NULL, 0);
+
+	if(o == NULL)
+		{
+			Runtime_Free(runt);
+			Executable_Free(exe);
+			return NULL;
+		}
+
+	Runtime_Free(runt);
+	Executable_Free(exe);
+	return o;
+}
\ No newline at end of file
diff --git a/src/eval.h b/src/eval.h
new file mode 100644
index 0000000..6fef22f
--- /dev/null
+++ b/src/eval.h
@@ -0,0 +1,3 @@
+#include "utils/error.h"
+#include "objects/objects.h"
+Object *eval(const char *str, int len, Object *closure, Heap *heap, Error *error);
\ No newline at end of file
diff --git a/src/main.c b/src/main.c
index 9f60976..5179436 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3,6 +3,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include "debug.h"
+#include "o_builtins.h"
 #include "compiler/parse.h"
 #include "compiler/serialize.h"
 #include "compiler/compile.h"
@@ -14,8 +15,6 @@
  * $ noja -f <file> -o <file>
  */
 
-Object *Object_NewBuiltinsMap(Runtime *runtime, Heap *heap, Error *err);
-
 typedef enum { RUN, HELP, PARSE, VERSION, DISASSEMBLY } Action;
 
 typedef struct {
diff --git a/src/o_builtins.c b/src/o_builtins.c
index caa403e..24f4310 100644
--- a/src/o_builtins.c
+++ b/src/o_builtins.c
@@ -4,8 +4,7 @@
 #include <stdlib.h>
 #include "runtime/runtime.h"
 #include "utils/defs.h"
-
-Object *Object_NewNetworkBuiltinsMap(Runtime *runtime, Heap *heap, Error *err);
+#include "o_builtins.h"
 
 static Object *select_(Object *self, Object *key, Heap *heap, Error *err);
 
diff --git a/src/o_builtins.h b/src/o_builtins.h
new file mode 100644
index 0000000..f5b02e6
--- /dev/null
+++ b/src/o_builtins.h
@@ -0,0 +1,3 @@
+#include "runtime/runtime.h"
+Object *Object_NewBuiltinsMap(Runtime *runtime, Heap *heap, Error *err);
+Object *Object_NewNetworkBuiltinsMap(Runtime *runtime, Heap *heap, Error *err);
\ No newline at end of file
diff --git a/src/objects/o_list.c b/src/objects/o_list.c
index 52bffe9..5296d98 100644
--- a/src/objects/o_list.c
+++ b/src/objects/o_list.c
@@ -1,4 +1,5 @@
 #include <assert.h>
+#include <string.h>
 #include "../utils/defs.h"
 #include "objects.h"
 
@@ -57,6 +58,21 @@ Object *Object_NewList(int capacity, Heap *heap, Error *error)
 	return (Object*) obj;
 }
 
+Object *Object_NewList2(int num, Object **items, Heap *heap, Error *error)
+{
+	assert(num > -1);
+
+	ListObject *list = (ListObject*) Object_NewList(num, heap, error);
+
+	if(list == NULL)
+		return NULL;
+
+	memcpy(list->vals, items, num * sizeof(Object*));
+	list->count = num;
+
+	return (Object*) list;
+}
+
 static void walk(Object *self, void (*callback)(Object **referer, void *userp), void *userp)
 {
 	ListObject *list = (ListObject*) self;
diff --git a/src/objects/objects.h b/src/objects/objects.h
index a79455a..72d9815 100644
--- a/src/objects/objects.h
+++ b/src/objects/objects.h
@@ -105,6 +105,7 @@ void 		 Object_WalkExtensions(Object *parent, void (*callback)(void   **referer,
 
 Object*		 Object_NewMap(int num, Heap *heap, Error *error);
 Object*		 Object_NewList(int capacity, Heap *heap, Error *error);
+Object*		 Object_NewList2(int num, Object **items, Heap *heap, Error *error);
 Object*		 Object_NewNone(Heap *heap, Error *error);
 Object*		 Object_NewBuffer(int size, Heap *heap, Error *error);
 Object*		 Object_NewClosure(Object *parent, Object *new_map, Heap *heap, Error *error);
diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index 76d4ac8..4ad2799 100644
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -9,6 +9,7 @@
 typedef struct xRuntime Runtime;
 typedef void CallStackScanner;
 Runtime*	Runtime_New(int stack_size, int heap_size, void *callback_userp, _Bool (*callback_addr)(Runtime*, void*));
+Runtime*	Runtime_New2(int stack_size, Heap *heap, _Bool free_heap, void *callback_userp, _Bool (*callback_addr)(Runtime*, void*));
 void 		Runtime_Free(Runtime *runtime);
 _Bool 		Runtime_Pop(Runtime *runtime, Error *error, unsigned int n);
 _Bool 		Runtime_Push(Runtime *runtime, Error *error, Object *obj);