From b0b048c03930b826ab3dbf88b56fd664fca26886 Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Fri, 22 May 2020 15:32:31 +0300
Subject: Add script command redirect aliases

---
 libbuild2/script/lexer.hxx | 53 ++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 6 deletions(-)

(limited to 'libbuild2/script/lexer.hxx')

diff --git a/libbuild2/script/lexer.hxx b/libbuild2/script/lexer.hxx
index c0d617d..bdeba66 100644
--- a/libbuild2/script/lexer.hxx
+++ b/libbuild2/script/lexer.hxx
@@ -33,21 +33,58 @@ namespace build2
       lexer_mode (base_type v): base_type (v) {}
     };
 
+    // Redirects the <, <<, <<<, >, >>, and >>> aliases resolve to.
+    //
+    struct redirect_aliases
+    {
+      optional<token_type> l;   // <
+      optional<token_type> ll;  // <<
+      optional<token_type> lll; // <<<
+      optional<token_type> g;   // >
+      optional<token_type> gg;  // >>
+      optional<token_type> ggg; // >>>
+
+      // If the token type is a redirect alias then return the token type
+      // it resolves to and the passed type otherwise. It's the caller's
+      // responsibility to make sure that the corresponding alias is present.
+      //
+      token_type
+      resolve (token_type t) const noexcept
+      {
+        switch (t)
+        {
+        case token_type::in_l:    assert (l);   return *l;
+        case token_type::in_ll:   assert (ll);  return *ll;
+        case token_type::in_lll:  assert (lll); return *lll;
+        case token_type::out_g:   assert (g);   return *g;
+        case token_type::out_gg:  assert (gg);  return *gg;
+        case token_type::out_ggg: assert (ggg); return *ggg;
+        }
+
+        return t;
+      }
+    };
+
     class lexer: public build2::lexer
     {
     public:
       using base_lexer = build2::lexer;
       using base_mode = build2::lexer_mode;
 
-      // Note that neither the name nor escape arguments are copied.
+      using redirect_aliases_type = script::redirect_aliases;
+
+      // Note that none of the name, redirect aliases, and escape arguments
+      // are copied.
       //
       lexer (istream& is,
              const path_name& name,
              lexer_mode m,
+             const redirect_aliases_type& ra,
              const char* escapes = nullptr)
           : base_lexer (is, name, 1 /* line */,
                         nullptr     /* escapes */,
-                        false       /* set_mode */)
+                        false       /* set_mode */),
+            redirect_aliases (ra)
       {
         mode (m, '\0', escapes);
       }
@@ -69,19 +106,23 @@ namespace build2
       virtual token
       next () override;
 
+    public:
+      const redirect_aliases_type& redirect_aliases;
+
     protected:
       lexer (istream& is, const path_name& name, uint64_t line,
              const char* escapes,
-             bool set_mode)
-          : base_lexer (is, name, line, escapes, set_mode) {}
+             bool set_mode,
+             const redirect_aliases_type& ra)
+          : base_lexer (is, name, line, escapes, set_mode),
+            redirect_aliases (ra) {}
 
       // Return the next token if it is a command operator (|, ||, &&,
       // redirect, or cleanup) and nullopt otherwise.
       //
       optional<token>
       next_cmd_op (const xchar&, // The token first character (last got char).
-                   bool sep,     // The token is separated.
-                   lexer_mode);  // The current (potentially "expired") mode.
+                   bool sep);    // The token is separated.
 
     private:
       token
-- 
cgit v1.1