marfrit
c9116c9bbf
Phase 0 binding per PHASE0.md §9. M.readline(prompt) returns the line as a Lua string (the C buffer is freed via libc free immediately after ffi.string copies it) or nil on EOF. M.add_history skips empty lines. Loader handles the case where libreadline-dev's unversioned `libreadline.so` symlink isn't installed — falls through to `readline.so.8` (current Debian/Arch ALARM) and `.so.7` (older) before giving up. This trips on noether-the-LXD: only the runtime package is present. Smoke (stdin from heredoc, two lines + EOF): p1> hello world -> "hello world" p2> second line -> "second line" p3> -> nil (EOF) Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
51 lines
1.4 KiB
Lua
51 lines
1.4 KiB
Lua
-- ffi/readline.lua — GNU readline binding.
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-- Phase 0: readline + add_history + EOF handling. Phase 1: custom key bindings.
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-- See docs/PHASE0.md §9.
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local ffi = require("ffi")
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ffi.cdef[[
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char *readline(const char *prompt);
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void add_history(const char *line);
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void free(void *ptr);
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]]
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-- libreadline-dev (which ships the unversioned `libreadline.so` symlink) is
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-- not assumed to be installed on the runtime host; fall back to versioned
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-- sonames so a base Debian/Arch with just libreadline runtime works.
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local function load_readline()
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local errs = {}
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for _, name in ipairs({"readline", "readline.so.8", "readline.so.7"}) do
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local ok, lib = pcall(ffi.load, name)
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if ok then return lib end
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errs[#errs+1] = name .. ": " .. tostring(lib)
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end
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error("libreadline not loadable: " .. table.concat(errs, "; "))
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end
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local rl = load_readline()
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local C = ffi.C
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local M = {}
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-- Read one line of input.
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-- Returns:
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-- string : the line (no trailing newline)
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-- nil : EOF (Ctrl-D on empty line)
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function M.readline(prompt)
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local cstr = rl.readline(prompt)
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if cstr == nil then return nil end
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local s = ffi.string(cstr)
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C.free(cstr)
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return s
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end
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-- Append a non-empty line to readline's in-memory history.
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function M.add_history(line)
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if line and #line > 0 then
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rl.add_history(line)
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end
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end
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return M
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