1function tostr(t)
2    local str = ""
3    for k, v in next, t do
4        if #str > 0 then
5            str = str .. ", "
6        end
7        if type(k) == "number" then
8            str = str .. "[" .. k .. "] = "
9        else
10            str = str .. tostring(k) .. " = "
11        end
12        if type(v) == "table" then
13            str = str .. "{ " .. tostr(v) .. " }"
14        elseif type(v) == "string" then
15            str = str .. '"' .. v .. '"'
16        else
17            str = str .. tostring(v)
18        end
19    end
20    return str
21end
22
23function trim_ws(s)
24    return s:match("^%s*(.*)")
25end
26
27function count_hypens(s)
28    local leftover = s:match("^-*(.*)")
29    return string.len(s) - string.len(leftover)
30end
31
32function pretty_print_slide(slide)
33    io.write("{\n")
34    if slide.transition then
35        io.write("   transition = \"", slide.transition, "\",\n")
36    end
37    for i = 1, #slide do
38        local node = slide[i]
39        for j = 0, node.indent do
40            io.write("   ")
41        end
42        io.write("{ ")
43        io.write(tostr(node))
44        io.write(" },\n")
45    end
46    io.write("},\n")
47end
48
49function pretty_print_slides(slides)
50    io.write("gSlides = {\n")
51    for i = 1, #slides do
52        pretty_print_slide(slides[i])
53    end
54    io.write("}\n")
55end
56
57function parse_attr(s, lvalue)
58    local ts = "^<%s*" .. lvalue .. "%s*=%s*(%a+)%s*>$"
59    return s:match(ts)
60end
61
62function flush(slides, block)
63    if #block > 0 then
64        slides[#slides + 1] = block
65        return {}
66    end
67    return block
68end
69
70function parse_file(file)
71    local slides = {}
72    local block = {}
73
74    for line in file:lines() do
75        local s = trim_ws(line)
76        if #s == 0 then   -- done with a block
77            block = flush(slides, block)
78        else
79            local transition_type = parse_attr(s, "transition")
80            local blockstyle = parse_attr(s, "blockstyle")
81            if transition_type then
82                block["transition"] = transition_type
83            elseif blockstyle then
84                block["blockstyle"] = blockstyle
85            else
86                if block.blockstyle == "code" then
87                    block[#block + 1] = { text = line }
88                else
89                    local n = count_hypens(s)
90                    block[#block + 1] = {
91                        indent = n,
92                        text = trim_ws(s:sub(n + 1, -1))
93                    }
94                end
95            end
96        end
97    end
98    flush(slides, block)
99
100    return slides
101end
102
103