gsl-shell.git - gsl-shell

diff --git a/mini-parser.lua b/mini-parser.lua
index feeb7e8a..abcb52d9 100644
--- a/mini-parser.lua
+++ b/mini-parser.lua

@@ -126,8 +126,41 @@ end

local AST_create = {

infix = function(sym, a, b) return {operator= sym, a, b} end,

- ident = function(id) return id end,

+ ident = function(id) return {ident= id} end,

prefix = function(sym, a) return {operator= sym, a} end,

}

-return {lexer = new_lexer, parse = parse_expr, AST= AST_create}

+local format = string.format

+local AST_print

+

+local function is_ident_simple(s)

+ return s:match('^[_%l%u]%w*$')

+end

+

+local function AST_print_op(e, prio)

+ if #e == 1 then

+ local c, c_prio = AST_print(e[1])

+ if c_prio < prio then c = format('(%s)', c) end

+ return format("%s%s", e.operator, c)

+ else

+ local a, a_prio = AST_print(e[1])

+ local b, b_prio = AST_print(e[2])

+ if a_prio < prio then a = format('(%s)', a) end

+ if b_prio < prio then b = format('(%s)', b) end

+ return format("%s %s %s", a, e.operator, b)

+ end

+end

+

+AST_print = function(e)

+ if e.ident then

+ local s = e.ident

+ if not is_ident_simple(s) then s = format('[%s]', s) end

+ return s, 3

+ else

+ local prio = priority_table[e.operator]

+ local s = AST_print_op(e, prio)

+ return s, prio

+ end

+end

+

+return {lexer = new_lexer, parse = parse_expr, AST= AST_create, print = AST_print}