Don't generate tables in the build.rs (do so in advance).

Cargo.toml

@@ -6,10 +6,11 @@ description = "Unicode caseless matching"
 repository = "https://github.com/SimonSapin/rust-caseless"
 license = "MIT"
 
-build = "src/build.rs"
-
-[build-dependencies]
-regex = "1.0"
-
 [dependencies]
 unicode-normalization = "0.1"
+
+[workspace]
+members = [
+    ".",
+    "print-table",
+]

print-table/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "print-table"
+version = "0.2.1"
+authors = ["Simon Sapin <[email protected]>"]
+license = "MIT"
+publish = false
+
+[dependencies]
+regex = "1"
+

src/build.rs → print-table/src/main.rs

@@ -1,17 +1,13 @@
 extern crate regex;
 
 use std::char;
-use std::env;
-use std::fs::File;
-use std::io::Write;
-use std::path::Path;
 use regex::Regex;
 
 // Case folding a single code point can give up to this many code points.
 const MAX_FOLDED_CODE_POINTS: usize = 3;
 
 fn main() {
-    let mut lines = include_str!("../CaseFolding.txt").lines();
+    let mut lines = include_str!("../../CaseFolding.txt").lines();
     let first_line = lines.next().unwrap();
     let version_regex = Regex::new(r"^# CaseFolding-(\d+)\.(\d+)\.(\d+).txt$").unwrap();
     let unicode_version = &version_regex.captures(first_line).unwrap();
@@ -21,15 +17,8 @@ fn main() {
         unicode_version[3].parse().unwrap(),
     );
 
-    let dst = Path::new(&env::var("OUT_DIR").unwrap()).join("case_folding_data.rs");
-    let f = &mut File::create(&dst).unwrap();
-
-    macro_rules! w {
-        ($($args: tt)+) => { (write!(f, $($args)+)).unwrap(); }
-    };
-
-    w!("pub const UNICODE_VERSION: (u64, u64, u64) = ({}, {}, {});\n", major, minor, patch);
-    w!("const CASE_FOLDING_TABLE: &'static [(char, [char; 3])] = &[\n");
+    print!("pub const UNICODE_VERSION: (u64, u64, u64) = ({}, {}, {});\n", major, minor, patch);
+    print!("pub const CASE_FOLDING_TABLE: &'static [(char, [char; 3])] = &[\n");
 
     // Entry with C (common case folding) or F (full case folding) status
     let c_or_f_entry = Regex::new(r"^([0-9A-F]+); [CF]; ([0-9A-F ]+);").unwrap();
@@ -42,17 +31,17 @@ fn main() {
             let blanks = MAX_FOLDED_CODE_POINTS - to.len();
             let mut to = to.into_iter();
             let first_to = to.next().unwrap();
-            w!("  ('{}', ['{}'", hex_to_escaped(from), first_to);
+            print!("  ('{}', ['{}'", hex_to_escaped(from), first_to);
             for c in to {
-                w!(", '{}'", c);
+                print!(", '{}'", c);
             }
             for _ in 0..blanks {
-                w!(", '\\0'");
+                print!(", '\\0'");
             }
-            w!("]),\n");
+            print!("]),\n");
         }
     }
-    w!("];\n");
+    print!("];\n");
 }