--- /dev/null
+-------------------------------------------------------------------------------
+-- Copyright (c) 2006-2013 Fabien Fleutot and others.
+--
+-- All rights reserved.
+--
+-- This program and the accompanying materials are made available
+-- under the terms of the Eclipse Public License v1.0 which
+-- accompanies this distribution, and is available at
+-- http://www.eclipse.org/legal/epl-v10.html
+--
+-- This program and the accompanying materials are also made available
+-- under the terms of the MIT public license which accompanies this
+-- distribution, and is available at http://www.lua.org/license.html
+--
+-- Contributors:
+-- Fabien Fleutot - API and implementation
+--
+-------------------------------------------------------------------------------
+
+-------------------------------------------------------------------------------
+--
+-- Summary: metalua parser, miscellaneous utility functions.
+--
+-------------------------------------------------------------------------------
+
+--------------------------------------------------------------------------------
+--
+-- Exported API:
+-- * [mlp.fget()]
+-- * [mlp.id()]
+-- * [mlp.opt_id()]
+-- * [mlp.id_list()]
+-- * [mlp.string()]
+-- * [mlp.opt_string()]
+-- * [mlp.id2string()]
+--
+--------------------------------------------------------------------------------
+
+local gg = require 'metalua.grammar.generator'
+
+-- TODO: replace splice-aware versions with naive ones, move etensions in ./meta
+
+return function(M)
+ local _M = gg.future(M)
+
+--[[ metaprog-free versions:
+ function M.id(lx)
+ if lx:peek().tag~='Id' then gg.parse_error(lx, "Identifier expected")
+ else return lx:next() end
+ end
+
+ function M.opt_id(lx)
+ if lx:peek().tag~='Id' then return lx:next() else return false end
+ end
+
+ function M.string(lx)
+ if lx:peek().tag~='String' then gg.parse_error(lx, "String expected")
+ else return lx:next() end
+ end
+
+ function M.opt_string(lx)
+ if lx:peek().tag~='String' then return lx:next() else return false end
+ end
+
+ --------------------------------------------------------------------------------
+ -- Converts an identifier into a string. Hopefully one day it'll handle
+ -- splices gracefully, but that proves quite tricky.
+ --------------------------------------------------------------------------------
+ function M.id2string (id)
+ if id.tag == "Id" then id.tag = "String"; return id
+ else error ("Identifier expected: "..table.tostring(id, 'nohash')) end
+ end
+--]]
+
+ --------------------------------------------------------------------------------
+ -- Try to read an identifier (possibly as a splice), or return [false] if no
+ -- id is found.
+ --------------------------------------------------------------------------------
+ function M.opt_id (lx)
+ local a = lx:peek();
+ if lx:is_keyword (a, "-{") then
+ local v = M.meta.splice(lx)
+ if v.tag ~= "Id" and v.tag ~= "Splice" then
+ gg.parse_error(lx, "Bad id splice")
+ end
+ return v
+ elseif a.tag == "Id" then return lx:next()
+ else return false end
+ end
+
+ --------------------------------------------------------------------------------
+ -- Mandatory reading of an id: causes an error if it can't read one.
+ --------------------------------------------------------------------------------
+ function M.id (lx)
+ return M.opt_id (lx) or gg.parse_error(lx,"Identifier expected")
+ end
+
+ --------------------------------------------------------------------------------
+ -- Common helper function
+ --------------------------------------------------------------------------------
+ M.id_list = gg.list { primary = _M.id, separators = "," }
+
+ --------------------------------------------------------------------------------
+ -- Converts an identifier into a string. Hopefully one day it'll handle
+ -- splices gracefully, but that proves quite tricky.
+ --------------------------------------------------------------------------------
+ function M.id2string (id)
+ --print("id2string:", disp.ast(id))
+ if id.tag == "Id" then id.tag = "String"; return id
+ elseif id.tag == "Splice" then
+ error ("id2string on splice not implemented")
+ -- Evaluating id[1] will produce `Id{ xxx },
+ -- and we want it to produce `String{ xxx }.
+ -- The following is the plain notation of:
+ -- +{ `String{ `Index{ `Splice{ -{id[1]} }, `Number 1 } } }
+ return { tag="String", { tag="Index", { tag="Splice", id[1] },
+ { tag="Number", 1 } } }
+ else error ("Identifier expected: "..table.tostring(id, 'nohash')) end
+ end
+
+ --------------------------------------------------------------------------------
+ -- Read a string, possibly spliced, or return an error if it can't
+ --------------------------------------------------------------------------------
+ function M.string (lx)
+ local a = lx:peek()
+ if lx:is_keyword (a, "-{") then
+ local v = M.meta.splice(lx)
+ if v.tag ~= "String" and v.tag ~= "Splice" then
+ gg.parse_error(lx,"Bad string splice")
+ end
+ return v
+ elseif a.tag == "String" then return lx:next()
+ else error "String expected" end
+ end
+
+ --------------------------------------------------------------------------------
+ -- Try to read a string, or return false if it can't. No splice allowed.
+ --------------------------------------------------------------------------------
+ function M.opt_string (lx)
+ return lx:peek().tag == "String" and lx:next()
+ end
+
+ --------------------------------------------------------------------------------
+ -- Chunk reader: block + Eof
+ --------------------------------------------------------------------------------
+ function M.skip_initial_sharp_comment (lx)
+ -- Dirty hack: I'm happily fondling lexer's private parts
+ -- FIXME: redundant with lexer:newstream()
+ lx :sync()
+ local i = lx.src:match ("^#.-\n()", lx.i)
+ if i then
+ lx.i = i
+ lx.column_offset = i
+ lx.line = lx.line and lx.line + 1 or 1
+ end
+ end
+
+ local function chunk (lx)
+ if lx:peek().tag == 'Eof' then
+ return { } -- handle empty files
+ else
+ M.skip_initial_sharp_comment (lx)
+ local chunk = M.block (lx)
+ if lx:peek().tag ~= "Eof" then
+ gg.parse_error(lx, "End-of-file expected")
+ end
+ return chunk
+ end
+ end
+
+ -- chunk is wrapped in a sequence so that it has a "transformer" field.
+ M.chunk = gg.sequence { chunk, builder = unpack }
+
+ return M
+end
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projects / metalua.git / blobdiff