overhaul number lexing / parsing

Cargo.toml

@@ -32,7 +32,7 @@ serialize = ["serde", "indexmap/serde-1"]
 deserialize = ["serde", "indexmap/serde-1"]
 spv-in = ["petgraph", "spirv"]
 spv-out = ["spirv"]
-wgsl-in = ["codespan-reporting", "hexf-parse", "unicode-xid"]
+wgsl-in = ["codespan-reporting", "hexf-parse", "unicode-xid", "lazy-regex"]
 wgsl-out = []
 hlsl-out = []
 span = ["codespan-reporting"]
@@ -65,6 +65,10 @@ hexf-parse = { version = "0.2.1", optional = true }
 # (but has no release that includes it yet)
 # https://github.com/unicode-rs/unicode-xid/pull/27
 unicode-xid = { version = "0.2.2", optional = true }
+lazy-regex = { version = "2.3.0", optional = true, default-features = false, features = ["std", "perf"] }
+# remove syn dep when updating to the next version of lazy-regex
+# see https://github.com/Canop/lazy-regex/pull/13
+syn = "1.0.22"
 
 [dev-dependencies]
 bincode = "1"