february.lua
· 3.5 KiB · Lua
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local program = [[
= [What is] February =
[February is] a syntax front end for nova , designed around streaming tokens .
= = =
~ [Many Rules] Many Delimiter ~
[February can] let you switch between them on the fly .
~ ~ ~
*** [A note] ***
SAYS you don't need those [backets] .
BUT they might help with clarity
*** *** [What is] February
*** *** ***
]]
local stream = program:gmatch(".")
local char, rule, rule_symbol, label_symbol, depth, symbol, side
local tuple, rules, LEFT, RIGHT = {}, {}, 1, 2
repeat
rule_symbol, char = "", stream()
side, rule = LEFT, {{}, {}}
while char and char:match("[%s%.,]") do
char = stream()
end
if char == nil then
break
elseif char == "[" then
depth, char = 1, stream()
while char do
if char == "[" then depth = depth + 1 end
if char == "]" then depth = depth - 1 end
if depth == 0 then break end
rule_symbol, char = rule_symbol .. char, stream()
end
else
rule_symbol = "" while char and not char:match("%s") do
rule_symbol, char = rule_symbol .. char, stream() if char == "[" then
io.stderr:write "Warning: symbol contains `[`. A space may be missing?"
end
end
end
repeat
char = stream()
while char and (char:match("[%s]") or not label_symbol and char:match("[%.,]")) do
char = stream()
end
if not char then
if label_symbol then
table.insert(rule[side], {label_symbol, tuple})
end
break
end
if char:match("[%.,]") then
symbol = char
elseif char == "[" then
symbol, depth, char = "", 1, stream() while char do
if char == "[" then depth = depth + 1 end
if char == "]" then depth = depth - 1 end
if depth == 0 then break end
symbol, char = symbol .. char, stream()
end
else
symbol = "" while char and not char:match("%s") do
symbol, char = symbol .. char, stream() if char == "[" then
io.stderr:write "Warning: symbol contains `[`. A space may be missing?"
end
end
end
if symbol == "," then
table.insert(rule[side], {label_symbol, tuple})
tuple = {}
elseif symbol == "." then
table.insert(rule[side], {label_symbol, tuple})
tuple, label_symbol = {}, nil
elseif symbol == rule_symbol and side == RIGHT then
if label_symbol then
table.insert(rule[side], {label_symbol, tuple})
tuple = {}
end
if #rule[LEFT] == 0 and #rule[RIGHT] == 0 then
break
else
table.insert(rules, rule)
side, rule, label_symbol = LEFT, {{}, {}}, nil
end
elseif symbol == rule_symbol and side == LEFT then
if label_symbol then
table.insert(rule[side], {label_symbol, tuple})
end
tuple, side, label_symbol = {}, RIGHT, nil
elseif not label_symbol then
label_symbol = symbol
else
table.insert(tuple, symbol)
end
until not char
if #rule[LEFT] ~= 0 or #rule[RIGHT] ~= 0 then
table.insert(rules, rule)
end
until not char
| 1 | local program = [[ |
| 2 | = [What is] February = |
| 3 | [February is] a syntax front end for nova , designed around streaming tokens . |
| 4 | = = = |
| 5 | |
| 6 | ~ [Many Rules] Many Delimiter ~ |
| 7 | [February can] let you switch between them on the fly . |
| 8 | ~ ~ ~ |
| 9 | |
| 10 | *** [A note] *** |
| 11 | SAYS you don't need those [backets] . |
| 12 | BUT they might help with clarity |
| 13 | |
| 14 | *** *** [What is] February |
| 15 | *** *** *** |
| 16 | ]] |
| 17 | local stream = program:gmatch(".") |
| 18 | local char, rule, rule_symbol, label_symbol, depth, symbol, side |
| 19 | local tuple, rules, LEFT, RIGHT = {}, {}, 1, 2 |
| 20 | repeat |
| 21 | rule_symbol, char = "", stream() |
| 22 | side, rule = LEFT, {{}, {}} |
| 23 | while char and char:match("[%s%.,]") do |
| 24 | char = stream() |
| 25 | end |
| 26 | if char == nil then |
| 27 | break |
| 28 | elseif char == "[" then |
| 29 | depth, char = 1, stream() |
| 30 | while char do |
| 31 | if char == "[" then depth = depth + 1 end |
| 32 | if char == "]" then depth = depth - 1 end |
| 33 | if depth == 0 then break end |
| 34 | rule_symbol, char = rule_symbol .. char, stream() |
| 35 | end |
| 36 | else |
| 37 | rule_symbol = "" while char and not char:match("%s") do |
| 38 | rule_symbol, char = rule_symbol .. char, stream() if char == "[" then |
| 39 | io.stderr:write "Warning: symbol contains `[`. A space may be missing?" |
| 40 | end |
| 41 | end |
| 42 | end |
| 43 | repeat |
| 44 | char = stream() |
| 45 | while char and (char:match("[%s]") or not label_symbol and char:match("[%.,]")) do |
| 46 | char = stream() |
| 47 | end |
| 48 | if not char then |
| 49 | if label_symbol then |
| 50 | table.insert(rule[side], {label_symbol, tuple}) |
| 51 | end |
| 52 | break |
| 53 | end |
| 54 | if char:match("[%.,]") then |
| 55 | symbol = char |
| 56 | elseif char == "[" then |
| 57 | symbol, depth, char = "", 1, stream() while char do |
| 58 | if char == "[" then depth = depth + 1 end |
| 59 | if char == "]" then depth = depth - 1 end |
| 60 | if depth == 0 then break end |
| 61 | symbol, char = symbol .. char, stream() |
| 62 | end |
| 63 | else |
| 64 | symbol = "" while char and not char:match("%s") do |
| 65 | symbol, char = symbol .. char, stream() if char == "[" then |
| 66 | io.stderr:write "Warning: symbol contains `[`. A space may be missing?" |
| 67 | end |
| 68 | end |
| 69 | end |
| 70 | if symbol == "," then |
| 71 | table.insert(rule[side], {label_symbol, tuple}) |
| 72 | tuple = {} |
| 73 | elseif symbol == "." then |
| 74 | table.insert(rule[side], {label_symbol, tuple}) |
| 75 | tuple, label_symbol = {}, nil |
| 76 | elseif symbol == rule_symbol and side == RIGHT then |
| 77 | if label_symbol then |
| 78 | table.insert(rule[side], {label_symbol, tuple}) |
| 79 | tuple = {} |
| 80 | end |
| 81 | if #rule[LEFT] == 0 and #rule[RIGHT] == 0 then |
| 82 | break |
| 83 | else |
| 84 | table.insert(rules, rule) |
| 85 | side, rule, label_symbol = LEFT, {{}, {}}, nil |
| 86 | end |
| 87 | elseif symbol == rule_symbol and side == LEFT then |
| 88 | if label_symbol then |
| 89 | table.insert(rule[side], {label_symbol, tuple}) |
| 90 | end |
| 91 | tuple, side, label_symbol = {}, RIGHT, nil |
| 92 | elseif not label_symbol then |
| 93 | label_symbol = symbol |
| 94 | else |
| 95 | table.insert(tuple, symbol) |
| 96 | end |
| 97 | until not char |
| 98 | if #rule[LEFT] ~= 0 or #rule[RIGHT] ~= 0 then |
| 99 | table.insert(rules, rule) |
| 100 | end |
| 101 | until not char |