diff --git a/CMakeLists.txt b/CMakeLists.txt
index e0fac59..a95b238 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -30,9 +30,17 @@ if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/src/scanner.c)
 endif()
 target_include_directories(tree-sitter-yaml PRIVATE src)
 
+set(YAML_SCHEMA core CACHE STRING "YAML schema")
+set(YAML_SCHEMA_VALUES core json legacy CACHE INTERNAL "Allowed schemas")
+set_property(CACHE YAML_SCHEMA PROPERTY STRINGS ${YAML_SCHEMA_VALUES})
+if(NOT YAML_SCHEMA IN_LIST YAML_SCHEMA_VALUES)
+    message(FATAL_ERROR "YAML_SCHEMA must be one of ${YAML_SCHEMA_VALUES}")
+endif()
+
 target_compile_definitions(tree-sitter-yaml PRIVATE
                            $<$<BOOL:${TREE_SITTER_REUSE_ALLOCATOR}>:TREE_SITTER_REUSE_ALLOCATOR>
-                           $<$<CONFIG:Debug>:TREE_SITTER_DEBUG>)
+                           $<$<CONFIG:Debug>:TREE_SITTER_DEBUG>
+                           YAML_SCHEMA=${YAML_SCHEMA})
 
 set_target_properties(tree-sitter-yaml
                       PROPERTIES
diff --git a/Makefile b/Makefile
index f924e2f..35cac8c 100644
--- a/Makefile
+++ b/Makefile
@@ -20,12 +20,18 @@ PCLIBDIR ?= $(LIBDIR)/pkgconfig
 
 # source/object files
 PARSER := $(SRC_DIR)/parser.c
-EXTRAS := $(filter-out $(PARSER),$(wildcard $(SRC_DIR)/*.c))
+EXTRAS := $(SRC_DIR)/scanner.c
 OBJS := $(patsubst %.c,%.o,$(PARSER) $(EXTRAS))
 
+# schema
+YAML_SCHEMA := core
+ifeq ($(filter $(YAML_SCHEMA),core json legacy),)
+$(error YAML_SCHEMA must be one of core/json/legacy)
+endif
+
 # flags
 ARFLAGS ?= rcs
-override CFLAGS += -I$(SRC_DIR) -std=c11 -fPIC
+override CFLAGS += -I$(SRC_DIR) -std=c11 -fPIC -DYAML_SCHEMA=$(YAML_SCHEMA)
 
 # ABI versioning
 SONAME_MAJOR = $(shell sed -n 's/\#define LANGUAGE_VERSION //p' $(PARSER))