X-Git-Url: https://git.stderr.nl/gitweb?p=matthijs%2Fmaster-project%2Freport.git;a=blobdiff_plain;f=pret-lam.lua;h=7058f620f01d5a8f2298418e9842f1137e86210b;hp=aff6988d8af774ef8f1e1021f954ed3f34e786d9;hb=bd1a6654263a93a66d1872334831bf69fc98610e;hpb=ba27dfb753703acfda3d7165ab2c0a334515c310

diff --git a/pret-lam.lua b/pret-lam.lua
index aff6988..7058f62 100644
--- a/pret-lam.lua
+++ b/pret-lam.lua
@@ -6,7 +6,7 @@
 
 local utf = unicode.utf8
 
-vis = buffers.newvisualizer("lam")
+local vis = buffers.newvisualizer("lam")
 
 local colors = {
     "prettytwo",
@@ -24,17 +24,25 @@ local symbols = {
     -- better.
     ['*'] = {repr = '\\ast'},
     ['~'] = {repr = '\\sim'},
+    ['|'] = {repr = '\\char' .. utf.byte('|')},
 }
 
-
 -- Keywords that should be bold
 local keywords = {
     ['case'] = {},
     ['of'] = {},
     ['let'] = {},
+    ['letrec'] = {},
+    ['letnonrec'] = {},
     ['in'] = {},
 }
 
+local in_block = 0
+local submatches = {}
+local bases = {}
+-- Store the last line for each indent level
+local indentlines = {}
+
 -- See if str starts with a symbol, and return the remaining string and that
 -- symbol. If no symbol from the table is matched, just returns the first
 -- character.  We can do a lookup directly, since symbols can be different in
@@ -63,7 +71,7 @@ end
 local function take_word(str)
         -- A word must always start with a-z (in particular, λ is not a valid
         -- start of a word).
-        res, newstr = utf.match(str, "^([a-zA-Z][%a%d_]+)(.*)")
+        res, newstr = utf.match(str, "^([a-zA-Z][%a%d%+%-%,_]+)(.*)")
         return res, newstr or str
 end
 
@@ -90,22 +98,108 @@ local function do_subscripts(word)
         if not bases[base] then
             -- Register that we've added this base
             bases[base] = true
-            -- Add a pattern for this base
-            submatches[#submatches+1] = "^(" .. base .. ")([%a%d,]+)$"
+            -- Add a patterns for this base. First, the base with a single
+            -- letter or number subscript.
+            submatches[#submatches+1] = "^(" .. base .. ")([%a%d])$"
+            -- Seconde, the base with a longer prefix that includes at least
+            -- one of +-, (to catch things like ri+1, but not return).
+            submatches[#submatches+1] = "^(" .. base .. ")([%a%d]*[%-%+%,]+[%a%d%-%+%,]*)$"
         end
     end
     return word
 end
 
+-- Do proper aligning for subsequent lines. For example, in 
+--   foo = bar
+--       | baz
+-- We replace the spaces in the second line with a skip with the same with as
+-- "foo ", to align the | with the =.
+-- For this, we keep a table "indentlines", which contains all previous lines
+-- with smaller indent levels that are still "in scope" (e.g., have not yet
+-- been followed by a line with a smaller indent level). For example:
+--   line1
+--     line2
+--       line3
+--     line4
+--       line5
+-- After the last line, the table will contain:
+--   { 0 = "line1", 2 = "  line4", 4 = "    line5"}
+--   In other words, line3 is no longer in scope since it is "hidden" by
+--   line4, and line is no longer in scope since it is replaced by line4.
+local function do_indent(line)
+    newind, rest = utf.match(line, '^(%s*)(.*)')
+    prev = -1
+    -- Loop all the previous lines
+    for indent, unused in pairs(indentlines) do
+        if indent > #newind then
+            -- Remove any lines with a larger indent
+            indentlines[indent] = nil
+        elseif indent < #newind and indent > prev then
+            -- Find the last line (e.g, with the highest indent) with an
+            -- indent smaller than the new indent. This is the line from which
+            -- we need to copy the indent.
+            prev = indent
+        end
+    end
+    
+    -- Always store this line, possibly overwriting a previous line with the
+    -- same indent
+    indentlines[#newind] = line
+
+    if prev ~= -1 then
+        -- If there is a previous line with a smaller indent, make sure we
+        -- align with it. We do this by taking a prefix from that previous
+        -- line just as long as our indent. This gives us a bunch of
+        -- whitespace, with a few non-whitespace characters. We find out the
+        -- width of this prefix, and put whitespace just as wide as that
+        -- prefix before the current line, instead of the whitespace
+        -- characters that were there.
+        -- Doing this is slightly risky, since the prefix might contain
+        -- unfinished markup (e.g., \foo{bar without the closing }). We might
+        -- need to solve this later.
+        copyind = utf.sub(indentlines[prev], 1, #newind)
+        setwidth = "\\setwidthof{" .. copyind .. "}\\to\\pretlamalignwidth"
+        hskip = "\\hskip\\pretlamalignwidth"
+        return "{" .. setwidth .. hskip .. "}" .. rest
+    end
+        -- No previous line? Just return the unmodified line then
+        return line
+end
+
+
+-- Mark the begin of a block of lambda formatted buffers or expressions. This
+-- means that, until you call end_of_block again, the subscript bases are
+-- shared. For example, if you have \lam{y1} some text \lam{yn} within a
+-- single block, the yn will properly get subscripted. Be sure to call
+-- end_of_block again!
+--
+-- Blocks can be partially nested, meaning that the block
+-- won't be closed until end_of_block was called exactly as often as
+-- begin_of_block. However, subscripts from the inner block can still
+-- influence subscripts in the outer block.
+function vis.begin_of_block()
+    vis.begin_of_display()
+    in_block = in_block + 1
+end
+
+-- Ends the current block
+function vis.end_of_block()
+    in_block = in_block - 1
+end
+
 function vis.begin_of_display()
-    -- Initially allow subscripts using _ or just appending a number (later,
-    -- we will add extra patterns here.
-    submatches = {"^(.*)_([%a%d,]+)$", "^(.*[^%d])(%d+)$"}
-    -- This stores all the bases we've encountered so far (to prevent
-    -- duplicates). For each of them there will be a pattern in submatches
-    -- above.
-    bases = {}
+    if in_block == 0 then
+        -- Initially allow subscripts using _ or just appending a number (later,
+        -- we will add extra patterns here.
+        submatches = {"^(%a*)_([%a%d,]+)$", "^(%a+)(%d+)$"}
+        -- This stores all the bases we've encountered so far (to prevent
+        -- duplicates). For each of them there will be a pattern in submatches
+        -- above.
+        bases = {}
+    end
+    indentlines = {}
 end
+    
 
 -- Make things work for inline typeing (e.g., \type{}) as well.
 vis.begin_of_inline = vis.begin_of_display
@@ -114,6 +208,7 @@ vis.end_of_inline = vis.end_of_display
 function vis.flush_line(str,nested)
     local result, state = { }, 0
     local finish, change = buffers.finish_state, buffers.change_state
+    str = do_indent(str)
     -- Set the colorscheme, which is used by finish_state and change_state
     buffers.currentcolors = colors
     while str ~= "" do
@@ -137,7 +232,7 @@ function vis.flush_line(str,nested)
         -- Append the resulting token
         result[#result+1] = word or symbol
     end
-
+    
     state = finish(state, result)
     buffers.flush_result(result,nested)
 end