Revert order of arguments to option::maybe and from_maybe

Closes #2019

Author: marijnh

src/libcore/option.rs

@@ -52,13 +52,13 @@ pure fn is_some<T>(opt: option<T>) -> bool {
     !is_none(opt)
 }
 
-pure fn from_maybe<T: copy>(def: T, opt: option<T>) -> T {
+pure fn from_maybe<T: copy>(opt: option<T>, def: T) -> T {
     #[doc = "Returns the contained value or a default"];
 
     alt opt { some(x) { x } none { def } }
 }
 
-fn maybe<T, U: copy>(def: U, opt: option<T>, f: fn(T) -> U) -> U {
+fn maybe<T, U: copy>(opt: option<T>, def: U, f: fn(T) -> U) -> U {
     #[doc = "Applies a function to the contained value or returns a default"];
 
     alt opt { none { def } some(t) { f(t) } }

src/libcore/os.rs

@@ -372,7 +372,7 @@ fn homedir() -> option<path> {
 
     #[cfg(target_os = "win32")]
     fn secondary() -> option<path> {
-        option::maybe(none, getenv("USERPROFILE")) {|p|
+        option::chain(getenv("USERPROFILE")) {|p|
             if !str::is_empty(p) {
                 some(p)
             } else {

src/rustc/driver/diagnostic.rs

@@ -245,7 +245,7 @@ fn highlight_lines(cm: codemap::codemap, sp: span,
 
 fn print_macro_backtrace(cm: codemap::codemap, sp: span) {
     option::may (sp.expn_info) {|ei|
-        let ss = option::maybe("", ei.callie.span,
+        let ss = option::maybe(ei.callie.span, "",
                                bind codemap::span_to_str(_, cm));
         print_diagnostic(ss, note,
                          #fmt("in expansion of #%s", ei.callie.name));

src/rustc/metadata/cstore.rs

@@ -163,7 +163,7 @@ fn get_dep_hashes(cstore: cstore) -> [str] {
 
 fn get_path(cstore: cstore, d: ast::def_id) -> [str] {
     // let f = bind str::split_str(_, "::");
-    option::maybe([], p(cstore).mod_path_map.find(d),
+    option::maybe(p(cstore).mod_path_map.find(d), [],
                   {|ds| str::split_str(ds, "::")})
 }
 // Local Variables:

src/rustc/middle/tstate/states.rs

@@ -616,7 +616,7 @@ fn find_pre_post_state_expr(fcx: fn_ctxt, pres: prestate, e: @expr) -> bool {
         handle_fail(fcx, pres, post);
         ret set_prestate_ann(fcx.ccx, e.id, pres) |
                 set_poststate_ann(fcx.ccx, e.id, post) |
-                option::maybe(false, maybe_fail_val, {|fail_val|
+                option::maybe(maybe_fail_val, false, {|fail_val|
                         find_pre_post_state_expr(fcx, pres, fail_val)});
       }
       expr_assert(p) {

src/rustc/middle/ty.rs

@@ -356,7 +356,7 @@ fn mk_ctxt(s: session::session, dm: resolve::def_map, amap: ast_map::map,
            region_map: @middle::region::region_map) -> ctxt {
     let interner = map::hashmap({|&&k: intern_key|
         hash_type_structure(k.struct) +
-            option::maybe(0u, k.o_def_id, ast_util::hash_def_id)
+            option::maybe(k.o_def_id, 0u, ast_util::hash_def_id)
     }, {|&&a, &&b| a == b});
     @{interner: interner,
       mutable next_id: 0u,

src/rustc/syntax/parse/eval.rs

@@ -25,7 +25,7 @@ fn eval_crate_directives_to_mod(cx: ctx, cdirs: [@ast::crate_directive],
     -> (ast::_mod, [ast::attribute]) {
     #debug("eval crate prefix: %s", prefix);
     #debug("eval crate suffix: %s",
-           option::from_maybe("none", suffix));
+           option::from_maybe(suffix, "none"));
     let (cview_items, citems, cattrs)
         = parse_companion_mod(cx, prefix, suffix);
     let view_items: [@ast::view_item] = [];

src/rustdoc/attr_pass.rs

@@ -50,7 +50,7 @@ fn fold_crate(
     {
         topmod: {
             item: {
-                name: option::from_maybe(doc.topmod.name(), attrs.name)
+                name: option::from_maybe(attrs.name, doc.topmod.name())
                 with doc.topmod.item
             }
             with doc.topmod

src/rustdoc/config.rs

@@ -125,14 +125,14 @@ fn config_from_opts(
     let result = result::chain(result) {|config|
         let output_dir = getopts::opt_maybe_str(match, opt_output_dir());
         result::ok({
-            output_dir: option::from_maybe(config.output_dir, output_dir)
+            output_dir: option::from_maybe(output_dir, config.output_dir)
             with config
         })
     };
     let result = result::chain(result) {|config|
         let output_format = getopts::opt_maybe_str(
             match, opt_output_format());
-        option::maybe(result::ok(config), output_format) {|output_format|
+        option::maybe(output_format, result::ok(config)) {|output_format|
             result::chain(parse_output_format(output_format)) {|output_format|
                 result::ok({
                     output_format: output_format
@@ -143,7 +143,7 @@ fn config_from_opts(
     };
     let result = result::chain(result) {|config|
         let output_style = getopts::opt_maybe_str(match, opt_output_style());
-        option::maybe(result::ok(config), output_style) {|output_style|
+        option::maybe(output_style, result::ok(config)) {|output_style|
             result::chain(parse_output_style(output_style)) {|output_style|
                 result::ok({
                     output_style: output_style