WIP: factorization of lexer and parser implementation - gsl-shell.git - gsl-shell

diff --git a/expr-actions.lua b/expr-actions.lua
index 79862f97..17fc015e 100644
--- a/expr-actions.lua
+++ b/expr-actions.lua

@@ -1,4 +1,6 @@

+local type = type

+

local function mult(a, b)

if a == 1 then return b end

if b == 1 then return a end

@@ -27,6 +29,21 @@ end

local function ident_action(id) return id end

+-- return true iff expr is a variable (with enums or not).

+-- if it is a variable returns, in addition, the var_name and the enumeration flag

+local function is_variable(expr)

+ if type(expr) == 'string' then

+ local esc_name = string.match(expr, "^%%(.*)")

+ return true, esc_name or expr, (esc_name ~= nil)

+ else

+ return false

+ end

+end

+

+local function is_number(expr)

+ return type(expr) == 'number'

+end

+

return {

infix = infix_action,

ident = ident_action,

@@ -36,4 +53,7 @@ return {

number = function(x) return x end,

exprlist = function(a, ls) if ls then ls[#ls+1] = a else ls = {a} end; return ls end,

schema = function(x, y, conds) return {x= x, y= y, conds= conds} end,

+

+ is_variable = is_variable,

+ is_number = is_number,

}