86 lines
2.5 KiB
Lua
86 lines
2.5 KiB
Lua
local lpeg = require('lpeg')
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local etlua = require('etlua')
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local config = require("config")
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local args = {...}
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lpeg.locale(lpeg)
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local V,P,C,S,B,Cs = lpeg.V,lpeg.P,lpeg.C,lpeg.S,lpeg.B,lpeg.Cs
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--Identity function
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local ident = function(a) return a end
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--Lowercase and capitalize first letter
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local function capitalize(str)
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return string.lower(str):gsub("^(.)",string.upper)
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end
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--Trim whitespace
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local function trim(str)
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return str:match("^%s*(.-)%s*$")
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end
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--SQL like match anywhere
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local function like(str)
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return "%" .. str .. "%"
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end
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--Tags are always trimed of whitepsace, lowercase with first letter capitalized
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local function tag_fmt(str)
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return capitalize(trim(str))
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end
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--Title match
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local function title_fmt(str)
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return like(trim(str))
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end
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--Author names are all lowercase alphanumeric, max 30 characters
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local function author_fmt(str)
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return like(string.lower(trim(str)))
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end
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local fieldnames = {
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title = {name="title",type="string",fmt=title_fmt},
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author = {name="author",type="string",fmt=author_fmt},
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date = {name="date",type="number",fmt=tonumber},
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hits = {name="hits",type="number",fmt=tonumber},
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tags = {name="tag",type="string",fmt=tag_fmt},
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}
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local field_default = "tag"
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local fields
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local grammar = P{
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"chunk";
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whitespace = S" \t\n"^0,
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itm = C((P(1 - (P" " * S"+-")))^0), --go until the next '+' or '-'
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likefield = C(P"title" + P"author") * V"whitespace" * C(P"=") * V"whitespace" * V"itm",
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rangeop = P"<=" + P">=" + P">" + P"<" + P"=",
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rangefield = C(P"date" + P"hits") * V"whitespace" * C(V"rangeop") * V"whitespace" * C(V"itm"),
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field = C(S"+-") * (V"likefield" + V"rangefield" + V"itm") / function(pn,field,expr,value)
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if expr and value then
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fields[field] = fields[field] or {}
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table.insert(fields[field],{pn,expr,value})
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else
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fields.tags = fields.tags or {}
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table.insert(fields.tags,{pn,"=",field})
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end
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end,
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chunk = V"field" * (P" " * V"field")^0
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}
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--Grammar
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--Transpile a sting with + and - into an sql query that searches tags
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local fname = config.approot .. "pages/search_sql.etlua"
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local sqltmpl = assert(io.open(fname))
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local c = etlua.compile(sqltmpl:read("*a"),fname)
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sqltmpl:close()
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local function transpile(str)
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str = string.lower(str)
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fields = {tags={}}
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table.concat({grammar:match(str)}," ")
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--Sanity perform formatting on data
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for field,values in pairs(fields) do
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for _,value in pairs(values) do
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local pn, expr, val = unpack(value)
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local nval = fieldnames[field].fmt(val)
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value[3] = nval
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end
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end
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local ressql = c{
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result = fields
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}
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return ressql, fields
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end
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return transpile
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