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https://github.com/Reuh/anselme.git
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Étienne Reuh Fildadut
fe351b5ca4
Woke up and felt like changing a couple things. It's actually been worked on for a while, little at a time... The goal was to make the language and implementation much simpler. Well I don't know if it really ended up being simpler but it sure is more robust. Main changes: * proper first class functions and closures supports! proper scoping rules! no more namespace shenanigans! * everything is an expression, no more statements! make the implementation both simpler and more complex, but it's much more consistent now! the syntax has massively changed as a result though. * much more organized and easy to modify codebase: one file for each AST node, no more random fields or behavior set by some random node exceptionally, everything should now follow the same API defined in ast.abstract.Node Every foundational feature should be implemented right now. The vast majority of things that were possible in v2 are possible now; some things aren't, but that's usually because v2 is a bit more sane. The main missing things before a proper release are tests and documentation. There's a few other things that might be implemented later, see the ideas.md file.
78 lines
2.9 KiB
Lua
78 lines
2.9 KiB
Lua
-- note: this is reused in primary.text, hence all the configurable fields
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local primary = require("parser.expression.primary.primary")
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local StringInterpolation = require("ast.StringInterpolation")
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local ast = require("ast")
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local String = ast.String
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local expression_to_ast = require("parser.expression.to_ast")
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local escape = require("common").escape
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local escape_code = {
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["n"] = "\n",
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["t"] = "\t",
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-- everything else is identity by default
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}
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return primary {
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type = "string", -- interpolation type - used for errors
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start_pattern = "\"", -- pattern that start the string interpolation
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stop_char = "\"", -- character that stops the string interpolation - must be a single character!
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allow_implicit_stop = false, -- set to true to allow the string to be closed implicitely when reaching the end of the expression or limit_pattern
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interpolation = StringInterpolation,
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match = function(self, str)
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return str:match("^"..self.start_pattern)
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end,
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parse = function(self, source, str, limit_pattern)
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local interpolation = self.interpolation:new()
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local stop_pattern = escape(self.stop_char)
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local start_source = source:clone()
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local rem = source:consume(str:match("^("..self.start_pattern..")(.-)$"))
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while not rem:match("^"..stop_pattern) do
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local text_source = source:clone()
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local text
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text, rem = rem:match("^([^%{%\\"..stop_pattern.."]*)(.-)$") -- get all text until something potentially happens
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-- cut the text prematurely at limit_pattern if relevant
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if self.allow_implicit_stop and limit_pattern and text:match(limit_pattern) then
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local pos = text:match("()"..limit_pattern) -- limit_pattern can contain $, so can't directly extract with captures
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text, rem = source:count(text:sub(1, pos-1)), ("%s%s%s"):format(self.stop_char, text:sub(pos), rem)
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source:increment(-1)
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else
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source:count(text)
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end
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interpolation:insert(String:new(text):set_source(text_source))
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if rem:match("^%{") then
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local ok, exp
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ok, exp, rem = pcall(expression_to_ast, source, source:consume(rem:match("^(%{)(.*)$")), "%}")
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if not ok then error("invalid expression inside interpolation: "..exp, 0) end
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if not rem:match("^%s*%}") then error(("unexpected %q at end of interpolation"):format(rem), 0) end
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rem = source:consume(rem:match("^(%s*%})(.*)$"))
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interpolation:insert(exp)
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elseif rem:match("^\\") then
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text, rem = source:consume(rem:match("^(\\(.))(.*)$"))
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interpolation:insert(String:new(escape_code[text] or text))
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elseif not rem:match("^"..stop_pattern) then
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if not self.allow_implicit_stop or rem:match("[^%s]") then
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error(("unexpected %q at end of "..self.type):format(rem), 0)
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-- consumed everything until end-of-line, implicit stop allowed, close your eyes and imagine the text has been closed
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else
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rem = rem .. self.stop_char
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end
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end
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end
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rem = source:consume(rem:match("^("..stop_pattern..")(.*)$"))
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return interpolation:set_source(start_source), rem
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end
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}
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