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better uncoupling of grammar and backends, grammar now produces a mor…
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…e generic ast that the backends consume
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Fabio Mascarenhas committed Jan 25, 2010
1 parent 58ce96e commit 5ba2e4e
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Showing 4 changed files with 245 additions and 244 deletions.
281 changes: 139 additions & 142 deletions src/cosmo.lua
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Expand Up @@ -8,165 +8,162 @@ module(..., package.seeall)

yield = coroutine.yield

local preamble = [[
local is_callable, insert, concat, setmetatable, getmetatable, type, wrap, tostring = ...
local function prepare_env(env, parent)
local __index = function (t, k)
local v = env[k]
if not v then
v = parent[k]
end
return v
end
local __newindex = function (t, k, v)
env[k] = v
end
return setmetatable({ raw = env }, { __index = __index, __newindex = __newindex })
end
local id = function () end
local template_func = %s
return function (env, opts)
opts = opts or {}
local out = opts.out or {}
template_func(out, env)
return concat(out, opts.delim)
end
]]

local compiled_template = [[
local concat = table.concat
local insert = table.insert
local compile = compile
local getmetatable = getmetatable
local setmetatable = setmetatable
local is_callable = ...
local function prepare_env(env, parent)
local __index = function (t, k)
local v = env[k]
if not v then
v = parent[k]
end
return v
function (out, env)
if type(env) == "string" then env = { it = env } end
$parts[=[
insert(out, $quoted_text)
]=],
[=[
local selector = $parsed_selector
if not selector then selector = '' end
$if_subtemplate[==[
local subtemplates = {}
$subtemplates[===[
subtemplates[$i] = $subtemplate
]===]
$if_args[===[
for e, literal in wrap(selector), $args, true do
if literal then
insert(out, tostring(e))
else
if type(e) ~= "table" then
e = prepare_env({ it = tostring(e) }, env)
else
e = prepare_env(e, env)
end
(subtemplates[e.raw._template or 1] or id)(out, e)
end
end
]===],
[===[
if type(selector) == 'table' then
for _, e in ipairs(selector) do
if type(e) ~= "table" then
e = prepare_env({ it = tostring(e) }, env)
else
e = prepare_env(e, env)
end
(subtemplates[e.raw._template or 1] or id)(out, e)
end
else
for e, literal in wrap(selector), nil, true do
if literal then
insert(out, tostring(e))
else
if type(e) ~= "table" then
e = prepare_env({ it = tostring(e) }, env)
else
e = prepare_env(e, env)
end
local __newindex = function (t, k, v)
env[k] = v
end
return setmetatable({ raw = env }, { __index = __index, __newindex = __newindex })
end
local function id() return "" end
return function (env)
local out = {}
if type(env) == "string" then env = { it = env } end
$parts[=[
insert(out, $quoted_text)
]=],
[=[
local selector = $parsed_selector
if not selector then selector = '' end
$if_subtemplate[==[
local subtemplates = {}
$subtemplates[===[
subtemplates[$i] = compile($subtemplate)
]===]
$if_args[===[
for e, literal in coroutine.wrap(selector), $args, true do
if literal then
insert(out, tostring(e))
else
if type(e) ~= "table" then
e = prepare_env({ it = tostring(e) }, env)
else
e = prepare_env(e, env)
end
insert(out, (subtemplates[e.raw._template or 1] or id)(e))
end
end
]===],
[===[
if type(selector) == 'table' then
for _, e in ipairs(selector) do
if type(e) ~= "table" then
e = prepare_env({ it = tostring(e) }, env)
else
e = prepare_env(e, env)
end
insert(out, (subtemplates[e.raw._template or 1] or id)(e))
end
else
for e, literal in coroutine.wrap(selector), nil, true do
if literal then
insert(out, tostring(e))
else
if type(e) ~= "table" then
e = prepare_env({ it = tostring(e) }, env)
else
e = prepare_env(e, env)
end
insert(out, (subtemplates[e.raw._template or 1] or id)(e))
end
end
end
]===]
]==],
[==[
$if_args[===[
selector = selector($args, false)
insert(out, tostring(selector))
]===],
[===[
if is_callable(selector) then
insert(out, tostring(selector()))
else
insert(out, tostring(selector))
end
]===]
]==]
]=]
return concat(out)
end
(subtemplates[e.raw._template or 1] or id)(out, e)
end
end
end
]===]
]==],
[==[
$if_args[===[
selector = selector($args, false)
insert(out, tostring(selector))
]===],
[===[
if is_callable(selector) then
insert(out, tostring(selector()))
else
insert(out, tostring(selector))
end
]===]
]==]
]=]
end
]]

local function compile_text(chunkname, text)
return { _template = 1, quoted_text = string.format("%q", text) }
local function is_callable(f)
if type(f) == "function" then return true end
local meta = getmetatable(f)
if meta and meta.__call then return true end
return false
end

local function compile_template(chunkname, template_code)
local template_func, err = loadstring(string.format(preamble, template_code), chunkname)
if not template_func then
error("syntax error when compiling template: " .. err)
else
return template_func(is_callable, table.insert, table.concat, setmetatable, getmetatable, type, coroutine.wrap, tostring)
end
end

local function parse_longstring(s)
local start = s:match("^(%[=*%[)")
if start then
return string.format("%q", s:sub(#start + 1, #s - #start))
else
return s
local compiler = {}

function compiler.template(template)
assert(template.tag == "template")
local parts = {}
for _, part in ipairs(template.parts) do
parts[#parts+1] = compiler[part.tag](part)
end
return interpreter.fill(compiled_template, { parts = parts })
end

local function compile_template_application(chunkname, selector, args, first_subtemplate,
subtemplates)
subtemplates = subtemplates or {}
if first_subtemplate ~= "" then
table.insert(subtemplates, 1, first_subtemplate)
end
function compiler.text(text)
assert(text.tag == "text")
return { _template = 1, quoted_text = string.format("%q", text.text) }
end

function compiler.appl(appl)
assert(appl.tag == "appl")
local selector, args, subtemplates = appl.selector, appl.args, appl.subtemplates
local ta = { _template = 2, selector = selector,
parsed_selector = selector }
local do_subtemplates = function ()
for i, subtemplate in ipairs(subtemplates) do
yield{ i = i, subtemplate = parse_longstring(subtemplate) }
end
for i, subtemplate in ipairs(subtemplates) do
yield{ i = i, subtemplate = compiler.template(subtemplate) }
end
end
if #subtemplates == 0 then
if args and args ~= "" and args ~= "{}" then
ta.if_subtemplate = { { _template = 2, if_args = { { _template = 1, args = args } } } }
else
ta.if_subtemplate = { { _template = 2, if_args = { { _template = 2 } } } }
end
if args and args ~= "" and args ~= "{}" then
ta.if_subtemplate = { { _template = 2, if_args = { { _template = 1, args = args } } } }
else
ta.if_subtemplate = { { _template = 2, if_args = { { _template = 2 } } } }
end
else
if args and args ~= "" and args ~= "{}" then
ta.if_subtemplate = { { _template = 1, subtemplates = do_subtemplates,
if_args = { { _template = 1, args = args } } } }
else
ta.if_subtemplate = { { _template = 1, subtemplates = do_subtemplates,
if_args = { { _template = 2 } } } }
end
if args and args ~= "" and args ~= "{}" then
ta.if_subtemplate = { { _template = 1, subtemplates = do_subtemplates,
if_args = { { _template = 1, args = args } } } }
else
ta.if_subtemplate = { { _template = 1, subtemplates = do_subtemplates,
if_args = { { _template = 2 } } } }
end
end
return ta
end

local function is_callable(f)
if type(f) == "function" then return true end
local meta = getmetatable(f)
if meta and meta.__call then return true end
return false
end

local function compile_template(chunkname, compiled_parts)
local template_code = interpreter.fill(compiled_template, { parts = compiled_parts })
local template_func, err = loadstring(template_code, chunkname)
if not template_func then
error("syntax error when compiling template: " .. err)
else
setfenv(template_func, _M)
return template_func(is_callable)
end
end

local compiler = grammar.cosmo_compiler{ text = compile_text,
template_application = compile_template_application,
template = compile_template }

local cache = {}
setmetatable(cache, { __index = function (tab, key)
local new = {}
Expand All @@ -180,7 +177,7 @@ function compile(template, chunkname)
chunkname = chunkname or template
local compiled_template = cache[template][chunkname]
if not compiled_template then
compiled_template = compiler:match(template, 1, chunkname)
compiled_template = compile_template(chunkname, compiler.template(grammar.ast:match(template, 1, {})))
cache[template][chunkname] = compiled_template
end
return compiled_template
Expand All @@ -196,7 +193,7 @@ function fill(template, env)
return compile(template)(env)
else
filled_templates[template] = true
return interpreter.fill(template, env, fill)
return interpreter.fill(template, env)
end
end

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