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|
----
-- Lpeg Grammar for parsing `alive` code.
--
-- @module parsing
import Constant from require 'alv.result'
import Cell from require 'alv.cell'
import Tag from require 'alv.tag'
import R, S, P, V, C, Ct from require 'lpeg'
-- whitespace
wc = S ' \t\r\n'
comment = P {
'comment',
expr: (P '(') * ((V 'expr') + (1 - P ')'))^0 * (P ')')
comment: (P '#(') * ((V 'expr') + (1 - P ')'))^0 * (P ')')
}
mspace = (comment + wc)^0 / 1 -- optional whitespace
space = (wc^1 * (comment^0 * wc)^0) / 1 -- required whitespace
-- atoms
digit = R '09'
first = (R 'az', 'AZ') + S '-_+*/.,=~!?%$><'
sym = first * (first + digit)^0 / Constant\parse 'sym'
strd = '"' * (C ((P '\\"') + (P '\\\\') + (1 - P '"'))^0) * '"' / Constant\parse 'str', '\"'
strq = "'" * (C ((P "\\'") + (P '\\\\') + (1 - P "'"))^0) * "'" / Constant\parse 'str', '\''
str = strd + strq
int = digit^1
float = (digit^1 * '.' * digit^0) + (digit^0 * '.' * digit^1)
num = ((P '-')^-1 * (float + int)) / Constant\parse 'num'
atom = num + sym + str
expr = (V 'cell') + atom
explist = Ct mspace * ((V 'expr') * (space * (V 'expr'))^0 * mspace)^-1
tag = (P '[') * (digit^1 / Tag.parse) * (P ']')
cell = (P '(') * tag^-1 * (V 'explist') * (P ')') / Cell.parse
root = P {
(V 'explist') / Cell.parse_root
:expr, :explist, :cell
}
cell = P {
'cell'
:expr, :explist, :cell
}
program = root * -1
--- exports
-- @table exports
-- @tfield pattern comment
-- @tfield pattern space
-- @tfield pattern atom
-- @tfield pattern expr
-- @tfield pattern explist
-- @tfield pattern explist
-- @tfield pattern cell
-- @tfield pattern root
-- @tfield pattern program the main parsing entrypoint
{
:comment
:space
:atom
:expr
:explist
:cell
:root
:program
}
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