gsl-shell.git - gsl-shell

diff --git a/mini-parser.lua b/mini-parser.lua
index abcb52d9..b2d7f944 100644
--- a/mini-parser.lua
+++ b/mini-parser.lua

@@ -1,12 +1,13 @@

+local len, match = string.len, string.match

+

local mini_lexer = {}

local mini_lexer_mt = {

__index = mini_lexer,

}

-local operators = {'+', '*', '-', '/', '^'}

-local priority_table = {['+'] = 0, ['-'] = 0, ['*'] = 1, ['/'] = 1, ['/'] = 2}

+local oper_table = {['+'] = 0, ['-'] = 0, ['*'] = 1, ['/'] = 1, ['^'] = 2}

local function new_lexer(src)

local lexer = {n = 1, src= src}

@@ -30,33 +31,46 @@ function mini_lexer.incr(lexer, n)

lexer.n = lexer.n + (n or 1)

end

+function mini_lexer.match(lexer, pattern)

+ return match(lexer.src, '^' .. pattern, lexer.n)

+end

+

+function mini_lexer.consume(lexer, pattern)

+ local m = match(lexer.src, '^' .. pattern, lexer.n)

+ if m then

+ lexer.n = lexer.n + len(m)

+ return m

+ end

+end

+

function mini_lexer.next_token(lexer)

- local spc = lexer.src:match('%s*', lexer.n)

- lexer:incr(spc:len())

- if lexer.n > lexer.src:len() then return {type= 'EOF'} end

+ lexer:consume('%s*')

+ if lexer.n > len(lexer.src) then return {type= 'EOF'} end

local c = lexer:char()

if c == '[' then

- lexer:consume('[')

- local str = lexer.src:match('^[^%]]+', lexer.n)

- lexer.n = lexer.n + str:len()

- lexer:consume(']')

- return {type= 'ident', value= str}

+ local str = lexer:consume('%b[]')

+ return {type= 'ident', value= str:sub(2,-2)}

end

- for _, cx in ipairs(operators) do

- if c == cx then

- lexer:incr()

- return {type= 'operator', symbol= c, priority = priority_table[c]}

- end

+ if oper_table[c] then

+ local prio = oper_table[c]

+ lexer:incr()

+ return {type= 'operator', symbol= c, priority = prio}

end

if c == '(' or c == ')' then

lexer:incr()

return {type= c}

end

- if lexer.src:match('^[%l%u_]', lexer.n) then

- local str = lexer.src:match('^[%l%u_]%w*', lexer.n)

- lexer.n = lexer.n + str:len()

+ if lexer:match('[%l%u_]') then

+ local str = lexer:consume('[%l%u_]%w*')

return {type= 'ident', value= str}

end

+ if lexer:match('[1-9]') then

+ local str = lexer:consume('[1-9]%d*%.%d*')

+ if not str then

+ str = lexer:consume('[1-9]%d*')

+ end

+ return {type= 'number', value= tonumber(str)}

+ end

end

function mini_lexer.next(lexer)

@@ -85,6 +99,10 @@ local function factor(lexer, actions)

local id = token.value

lexer:next()

return actions.ident(id)

+ elseif token.type == 'number' then

+ local x = token.value

+ lexer:next()

+ return actions.number(x)

elseif token.type == '(' then

lexer:next()

local a = expr(lexer, actions, 0)

@@ -128,6 +146,7 @@ local AST_create = {

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

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

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

+ number = function(x) return {number= x} end,

}

local format = string.format

@@ -147,7 +166,8 @@ local function AST_print_op(e, prio)

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)

+ local temp = (prio < 2 and "%s %s %s" or "%s%s%s")

+ return format(temp, a, e.operator, b)

end

end

@@ -156,8 +176,10 @@ AST_print = function(e)

local s = e.ident

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

return s, 3

+ elseif e.number then

+ return e.number, 3

else

- local prio = priority_table[e.operator]

+ local prio = oper_table[e.operator]

local s = AST_print_op(e, prio)

return s, prio

end