Report coefficient names in linear regression function - gsl-shell.git - gsl-shell

diff --git a/lm-expr.lua b/lm-expr.lua
new file mode 100644
index 00000000..3c59d7c3
--- /dev/null
+++ b/lm-expr.lua

@@ -0,0 +1,26 @@

+local format = string.format

+

+local function as_char(v, prio)

+ if type(v) == 'table' and v.name then

+ return (v.prio < prio and format("(%s)", v.name) or v.name)

+ end

+ return tostring(v)

+end

+

+local var_name

+

+local var_name_mt = {

+ __add = function(a, b) return var_name(format("%s + %s", as_char(a, 0), as_char(b, 0)), 0) end,

+ __mul = function(a, b) return var_name(format("%s * %s", as_char(a, 2), as_char(b, 2)), 2) end,

+ __sub = function(a, b) return var_name(format("%s - %s", as_char(a, 0), as_char(b, 0)), 0) end,

+ __div = function(a, b) return var_name(format("%s / %s", as_char(a, 2), as_char(b, 2)), 2) end,

+ __pow = function(a, b) return var_name(format("%s^%s", as_char(a, 10), as_char(b, 10)), 10) end,

+ __unm = function(a) return var_name(format("-%s", as_char(a, 1)), 1) end,

+}

+

+var_name = function (name, prio)

+ local t = {prio= prio or 10, name= name}

+ return setmetatable(t, var_name_mt)

+end

+

+return var_name