diff --git a/bshell/script-block.c b/bshell/script-block.c
new file mode 100644
index 0000000..d496c01
--- /dev/null
+++ b/bshell/script-block.c
@@ -0,0 +1,338 @@
+#include "script-block.h"
+
+#include "status.h"
+
+#include <fx/reflection/function.h>
+#include <fx/string.h>
+#include <fx/vector.h>
+
+struct string_cache_entry {
+	unsigned long e_index;
+	fx_namemap_entry e_entry;
+};
+
+struct bshell_scriptblock_p {
+	/* pool values referenced by the text */
+	FX_VECTOR_DECLARE(fx_value, b_pool);
+	/* bytecode instructions */
+	FX_VECTOR_DECLARE(bshell_instruction, b_text);
+	/* string value cache */
+	fx_namemap b_strings;
+};
+
+static fx_status pool_destroy(void *p)
+{
+	fx_value_unset(p);
+	return FX_SUCCESS;
+}
+
+static fx_vector_ops pool_ops = {
+	.v_destroy = pool_destroy,
+};
+
+static void scriptblock_fini(fx_object *obj, void *priv)
+{
+	struct bshell_scriptblock_p *block = priv;
+
+	fx_vector_destroy(block->b_pool, &pool_ops);
+	fx_vector_destroy(block->b_text, NULL);
+}
+
+static size_t scriptblock_push_instruction(
+	struct bshell_scriptblock_p *block,
+	enum bshell_opcode opcode,
+	uint32_t arg)
+{
+	size_t offset = block->b_text.count * sizeof(bshell_instruction);
+	uint32_t instr = bshell_instruction_encode(opcode, arg);
+	fx_vector_push_back(block->b_text, &instr, NULL);
+	return offset;
+}
+
+static enum bshell_status scriptblock_read_instruction(
+	struct bshell_scriptblock_p *block,
+	size_t offset,
+	enum bshell_opcode *out_opcode,
+	uint32_t *out_arg)
+{
+	offset /= sizeof(bshell_instruction);
+	if (offset >= block->b_text.count) {
+		return BSHELL_ERR_INVALID_ARGUMENT;
+	}
+
+	enum bshell_opcode opcode;
+	uint32_t arg;
+	bshell_instruction_decode(block->b_text.items[offset], &opcode, &arg);
+
+	if (out_opcode) {
+		*out_opcode = opcode;
+	}
+
+	if (out_arg) {
+		*out_arg = arg;
+	}
+
+	return BSHELL_SUCCESS;
+}
+
+static void scriptblock_patch_instruction(
+	struct bshell_scriptblock_p *block,
+	size_t offset,
+	enum bshell_opcode opcode,
+	uint32_t arg)
+{
+	offset /= sizeof(bshell_instruction);
+	if (offset >= block->b_text.count) {
+		return;
+	}
+
+	block->b_text.items[offset] = bshell_instruction_encode(opcode, arg);
+}
+
+static void scriptblock_clear_text(struct bshell_scriptblock_p *block)
+{
+	block->b_text.count = 0;
+}
+
+static void scriptblock_get_text(
+	const struct bshell_scriptblock_p *block,
+	bshell_instruction **out_ptr,
+	size_t *out_count)
+{
+	if (out_ptr) {
+		*out_ptr = block->b_text.items;
+	}
+
+	if (out_count) {
+		*out_count = block->b_text.count;
+	}
+}
+
+static void scriptblock_get_pool(
+	const struct bshell_scriptblock_p *block,
+	fx_value **out_ptr,
+	size_t *out_count)
+{
+	if (out_ptr) {
+		*out_ptr = block->b_pool.items;
+	}
+
+	if (out_count) {
+		*out_count = block->b_pool.count;
+	}
+}
+
+static unsigned long scriptblock_add_pool_value(
+	struct bshell_scriptblock_p *block,
+	fx_value *value)
+{
+	unsigned long id = block->b_pool.count;
+	fx_value *slot = fx_vector_emplace_back(block->b_pool, &pool_ops);
+	if (!slot) {
+		return (unsigned long)-1;
+	}
+
+	fx_value_copy(slot, value);
+	return id;
+}
+
+static fx_value *scriptblock_get_pool_value(
+	const struct bshell_scriptblock_p *block,
+	unsigned long index,
+	fx_type_id expected_type)
+{
+	if (index >= block->b_pool.count) {
+		return NULL;
+	}
+
+	fx_value *value = &block->b_pool.items[index];
+	if (expected_type
+	    && fx_type_id_compare(value->v_type, expected_type) != 0) {
+		return NULL;
+	}
+
+	return value;
+}
+
+static unsigned long scriptblock_get_string(
+	struct bshell_scriptblock_p *block,
+	const char *s)
+{
+	struct string_cache_entry *cache_entry = NULL;
+	fx_string *str = NULL;
+
+	fx_namemap_entry *e = fx_namemap_get(&block->b_strings, s);
+	if (e) {
+		cache_entry = fx_unbox(struct string_cache_entry, e, e_entry);
+		return cache_entry->e_index;
+	}
+
+	cache_entry = malloc(sizeof *cache_entry);
+	if (!cache_entry) {
+		goto cleanup;
+	}
+
+	str = fx_string_create_from_cstr(s);
+	if (!str) {
+		goto cleanup;
+	}
+
+	unsigned long index = block->b_pool.count;
+	fx_value *slot = fx_vector_emplace_back(block->b_pool, &pool_ops);
+	if (!slot) {
+		goto cleanup;
+	}
+
+	*slot = FX_CSTR(s);
+
+	cache_entry->e_index = index;
+	fx_namemap_put(
+		&block->b_strings,
+		fx_string_get_cstr(str),
+		&cache_entry->e_entry);
+
+	return index;
+
+cleanup:
+	if (str) {
+		fx_string_unref(str);
+	}
+
+	if (cache_entry) {
+		free(cache_entry);
+	}
+
+	return POOL_INDEX_INVALID;
+}
+
+size_t bshell_scriptblock_push_instruction(
+	bshell_scriptblock *block,
+	enum bshell_opcode opcode,
+	uint32_t arg)
+{
+	FX_CLASS_DISPATCH_STATIC(
+		BSHELL_TYPE_SCRIPTBLOCK,
+		scriptblock_push_instruction,
+		block,
+		opcode,
+		arg);
+}
+
+enum bshell_status bshell_scriptblock_read_instruction(
+	bshell_scriptblock *block,
+	size_t offset,
+	enum bshell_opcode *out_opcode,
+	uint32_t *out_arg)
+{
+	FX_CLASS_DISPATCH_STATIC(
+		BSHELL_TYPE_SCRIPTBLOCK,
+		scriptblock_read_instruction,
+		block,
+		offset,
+		out_opcode,
+		out_arg);
+}
+
+void bshell_scriptblock_patch_instruction(
+	bshell_scriptblock *block,
+	size_t offset,
+	enum bshell_opcode opcode,
+	uint32_t arg)
+{
+	FX_CLASS_DISPATCH_STATIC_V(
+		BSHELL_TYPE_SCRIPTBLOCK,
+		scriptblock_patch_instruction,
+		block,
+		offset,
+		opcode,
+		arg);
+}
+
+void bshell_scriptblock_clear_text(bshell_scriptblock *block)
+{
+	FX_CLASS_DISPATCH_STATIC_V0(
+		BSHELL_TYPE_SCRIPTBLOCK,
+		scriptblock_clear_text,
+		block);
+}
+
+void bshell_scriptblock_get_text(
+	const bshell_scriptblock *block,
+	bshell_instruction **out_ptr,
+	size_t *out_count)
+{
+	FX_CLASS_DISPATCH_STATIC(
+		BSHELL_TYPE_SCRIPTBLOCK,
+		scriptblock_get_text,
+		block,
+		out_ptr,
+		out_count);
+}
+
+void bshell_scriptblock_get_pool(
+	const bshell_scriptblock *block,
+	fx_value **out_ptr,
+	size_t *out_count)
+{
+	FX_CLASS_DISPATCH_STATIC(
+		BSHELL_TYPE_SCRIPTBLOCK,
+		scriptblock_get_pool,
+		block,
+		out_ptr,
+		out_count);
+}
+
+unsigned long bshell_scriptblock_add_pool_value(
+	bshell_scriptblock *block,
+	fx_value *value)
+{
+	FX_CLASS_DISPATCH_STATIC(
+		BSHELL_TYPE_SCRIPTBLOCK,
+		scriptblock_add_pool_value,
+		block,
+		value);
+}
+
+fx_value *bshell_scriptblock_get_pool_value(
+	const bshell_scriptblock *block,
+	unsigned long index,
+	fx_type_id expected_type)
+{
+	FX_CLASS_DISPATCH_STATIC(
+		BSHELL_TYPE_SCRIPTBLOCK,
+		scriptblock_get_pool_value,
+		block,
+		index,
+		expected_type);
+}
+
+unsigned long bshell_scriptblock_get_string(
+	bshell_scriptblock *block,
+	const char *s)
+{
+	FX_CLASS_DISPATCH_STATIC(
+		BSHELL_TYPE_SCRIPTBLOCK,
+		scriptblock_get_string,
+		block,
+		s);
+}
+
+FX_TYPE_CLASS_BEGIN(bshell_scriptblock)
+	FX_TYPE_VTABLE_INTERFACE_BEGIN(fx_object, FX_TYPE_OBJECT)
+		FX_INTERFACE_ENTRY(to_string) = NULL;
+	FX_TYPE_VTABLE_INTERFACE_END(fx_object, FX_TYPE_OBJECT)
+
+	FX_TYPE_CONSTRUCTOR(
+		"create",
+		bshell_scriptblock_create,
+		0,
+		FX_TYPE_VOID);
+FX_TYPE_CLASS_END(bshell_scriptblock)
+
+FX_TYPE_DEFINITION_BEGIN(bshell_scriptblock)
+	FX_TYPE_ID(0x02b87313, 0x83f6, 0x4a57, 0xa573, 0x62cf492391ce);
+	FX_TYPE_NAME("bshell.scriptblock");
+	FX_TYPE_CLASS(bshell_scriptblock_class);
+	FX_TYPE_INSTANCE_PRIVATE(struct bshell_scriptblock_p);
+	FX_TYPE_INSTANCE_FINI(scriptblock_fini);
+FX_TYPE_DEFINITION_END(bshell_scriptblock)
diff --git a/bshell/script-block.h b/bshell/script-block.h
new file mode 100644
index 0000000..10e3451
--- /dev/null
+++ b/bshell/script-block.h
@@ -0,0 +1,62 @@
+#ifndef SCRIPT_BLOCK_H_
+#define SCRIPT_BLOCK_H_
+
+#include "runtime/opcode.h"
+
+#include <fx/macros.h>
+#include <fx/value.h>
+
+FX_DECLS_BEGIN;
+
+enum bshell_opcode;
+
+#define POOL_INDEX_INVALID      ((unsigned long)-1)
+#define BSHELL_TYPE_SCRIPTBLOCK (bshell_scriptblock_get_type())
+
+FX_DECLARE_TYPE(bshell_scriptblock);
+
+FX_TYPE_CLASS_DECLARATION_BEGIN(bshell_scriptblock)
+FX_TYPE_CLASS_DECLARATION_END(bshell_scriptblock)
+
+FX_DECLS_END;
+
+extern fx_type_id bshell_scriptblock_get_type(void);
+
+FX_TYPE_DEFAULT_CONSTRUCTOR(bshell_scriptblock, BSHELL_TYPE_SCRIPTBLOCK);
+
+extern size_t bshell_scriptblock_push_instruction(
+	bshell_scriptblock *block,
+	enum bshell_opcode opcode,
+	uint32_t arg);
+extern enum bshell_status bshell_scriptblock_read_instruction(
+	bshell_scriptblock *block,
+	size_t offset,
+	enum bshell_opcode *out_opcode,
+	uint32_t *out_arg);
+extern void bshell_scriptblock_patch_instruction(
+	bshell_scriptblock *block,
+	size_t offset,
+	enum bshell_opcode opcode,
+	uint32_t arg);
+
+extern void bshell_scriptblock_clear_text(bshell_scriptblock *block);
+extern void bshell_scriptblock_get_text(
+	const bshell_scriptblock *block,
+	bshell_instruction **out_ptr,
+	size_t *out_count);
+extern void bshell_scriptblock_get_pool(
+	const bshell_scriptblock *block,
+	fx_value **out_ptr,
+	size_t *out_count);
+extern unsigned long bshell_scriptblock_add_pool_value(
+	bshell_scriptblock *block,
+	fx_value *value);
+extern fx_value *bshell_scriptblock_get_pool_value(
+	const bshell_scriptblock *block,
+	unsigned long index,
+	fx_type_id expected_type);
+extern unsigned long bshell_scriptblock_get_string(
+	bshell_scriptblock *block,
+	const char *s);
+
+#endif