[Pratt Parser] Add Lexer

PiperOrigin-RevId: 953000456

Author: dmitriplotnikov

parser/internal/BUILD

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 load("@rules_cc//cc:cc_library.bzl", "cc_library")
+load("@rules_cc//cc:cc_test.bzl", "cc_test")
 load("//bazel:antlr.bzl", "antlr_cc_library")
 
 package(default_visibility = ["//visibility:public"])
@@ -29,3 +30,29 @@ antlr_cc_library(
     src = "Cel.g4",
     package = "cel_parser_internal",
 )
+
+cc_library(
+    name = "lexer",
+    srcs = ["lexer.cc"],
+    hdrs = ["lexer.h"],
+    deps = [
+        "//common:source",
+        "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/base:no_destructor",
+        "@com_google_absl//absl/container:flat_hash_map",
+        "@com_google_absl//absl/functional:function_ref",
+        "@com_google_absl//absl/log:absl_check",
+        "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/strings:string_view",
+    ],
+)
+
+cc_test(
+    name = "lexer_test",
+    srcs = ["lexer_test.cc"],
+    deps = [
+        ":lexer",
+        "//common:source",
+        "//internal:testing",
+    ],
+)