support tagging

5 files changed, 152 insertions, 63 deletions

diff --git a/ast.moon b/ast.moon
new file mode 100644
index 0000000..39e2f21
--- /dev/null
+++ b/ast.moon
@@ -0,0 +1,66 @@
+class Atom
+  new: (@raw, @style='', @value) =>
+
+  _walk_sexpr: =>
+
+  stringify: =>
+    switch @style
+      when ''
+        @raw
+      when '"'
+        "\"#{@raw}\""
+      else
+        error!
+
+  @make_num: (match) -> Atom match, '', tonumber match
+  @make_sym: (match) -> Atom match, '', match
+  @make_str: (match) -> Atom match, '"', match
+
+class Xpr
+  new: (parts, @style='(', tag) =>
+    @white = {}
+    @white[0] = parts[1]
+
+    for i = 2,#parts,2
+      @[i/2] = parts[i]
+      @white[i/2] = parts[i+1]
+
+    if tag
+      @tag = tag.value
+
+  _walk_sexpr: =>
+    if @style == '('
+      coroutine.yield @
+
+    for frag in *@
+      frag\_walk_sexpr!
+
+  walk_sexpr: =>
+    coroutine.wrap -> @_walk_sexpr!
+
+  stringify: =>
+    buf = ''
+    buf ..= @white[0]
+    for i, frag in ipairs @
+      buf ..= frag\stringify!
+      buf ..= @white[i]
+
+    switch @style
+      when 'naked'
+        buf
+      else
+        tag = if @tag then "[#{@tag}]" else ''
+        '(' .. tag .. buf .. ')'
+
+  make_sexpr: (tag, parts) ->
+    if parts
+      Xpr parts, '(', tag
+    else
+      Xpr tag, '('
+
+  make_nexpr: (parts) -> Xpr parts, 'naked'
+
+{
+  :Atom
+  :Xpr
+}
diff --git a/parsing.moon b/parsing.moon
index f9efef4..d4fba0b 100644
--- a/parsing.moon
+++ b/parsing.moon
@@ -1,47 +1,7 @@
 lpeg = require 'lpeg'
+import Atom, Xpr from require 'ast'
 
-class Atom
-  new: (@raw, @style='', @value) =>
-
-  stringify: =>
-    switch @style
-      when ''
-        @raw
-      when '"'
-        "\"#{@raw}\""
-      else
-        error!
-
-  @make_num: (match) -> Atom match, '', tonumber match
-  @make_sym: (match) -> Atom match, '', match
-  @make_str: (match) -> Atom match, '"', match
-
-class Xpr
-  new: (parts, @style='(') =>
-    @white = {}
-    @white[0] = parts[1]
-
-    for i = 2,#parts,2
-      @[i/2] = parts[i]
-      @white[i/2] = parts[i+1]
-
-  stringify: =>
-    buf = ''
-    buf ..= @white[0]
-    for i, frag in ipairs @
-      buf ..= frag\stringify!
-      buf ..= @white[i]
-
-    switch @style
-      when 'naked'
-        buf
-      else
-        '(' .. buf .. ')'
-
-  make_sexpr: (parts) -> Xpr parts, '('
-  make_nexpr: (parts) -> Xpr parts, 'naked'
-
-space = (lpeg.S ' \t\r\n') ^ 1 / 1
+space  = (lpeg.S ' \t\r\n') ^ 1 / 1
 mspace = (lpeg.S ' \t\r\n') ^ 0 / 1
 
 sym = ((lpeg.R 'az', 'AZ') + (lpeg.S '-_+*')) ^ 1 / Atom.make_sym
@@ -50,8 +10,10 @@ num = (lpeg.R '09', 'AZ') ^ 1 / Atom.make_num
 atom = sym + num + str
 
 expr = (lpeg.V 'sexpr') + atom
-explist = lpeg.Ct mspace * (lpeg.V 'expr') * (space * atom) ^ 0 * mspace
-sexpr = (lpeg.P '(') * (lpeg.V 'explist') * (lpeg.P ')') / Xpr.make_sexpr
+explist = lpeg.Ct mspace * (lpeg.V 'expr') * (space * (lpeg.V 'expr')) ^ 0 * mspace
+
+tag = (lpeg.P '[') * num * (lpeg.P ']')
+sexpr = (lpeg.P '(') * tag^-1 * (lpeg.V 'explist') * (lpeg.P ')') / Xpr.make_sexpr
 
 nexpr = lpeg.P {
   (lpeg.V 'explist') / Xpr.make_nexpr
@@ -63,7 +25,7 @@ sexpr = lpeg.P {
   :expr, :explist, :sexpr
 }
 
-program = nexpr
+program = nexpr * -1
 
 {
   :space
diff --git a/spec/ast_spec.moon b/spec/ast_spec.moon
new file mode 100644
index 0000000..402ce03
--- /dev/null
+++ b/spec/ast_spec.moon
@@ -0,0 +1,15 @@
+import Atom, Xpr from require 'ast'
+
+describe 'Xpr', ->
+  it 'can be walked', ->
+    aa = Xpr { '', (Atom '1', '', 1), '' }
+    ab = Xpr { '', (Atom '2', '', 2), '' }
+    ac = Xpr { '', (Atom '3', '', 3), '' }
+    b = Xpr { '', aa, ' ', ab, '' }
+
+    root = Xpr { '', ac, ' ', b, '' }, 'naked'
+
+    iter = root\walk_sexpr!
+    for res in *{ ac, b, aa, ab }
+      assert.is.equal res, iter!
+    assert.is.nil iter!
diff --git a/spec/peg_spec.moon b/spec/parsing_spec.moon
index 1b25406..5e6e1fc 100644
--- a/spec/peg_spec.moon
+++ b/spec/parsing_spec.moon
@@ -51,21 +51,50 @@ describe 'nexpr parsing', ->
 
     assert.is.equal ' 3\tok-yes\n', node\stringify!
 
-test 'sexpr parsing', ->
-  str = '( 3   ok-yes
-  "friend" )'
-  node = sexpr\match str
-
-  assert.is.equal '(', node.style
-  assert.is.equal 3, #node
-  assert.is.equal 3, node[1].value
-  assert.is.equal 'ok-yes', node[2].value
-  assert.is.equal 'friend', node[3].value
-
-  assert.is.equal str, node\stringify!
-
-test 'mixed parsing', ->
-  str = '( 3   ok-yes
-  "friend" )'
-  node = program\match str
-  assert.is.equal str, node\stringify!
+describe 'sexpr', ->
+  test 'basic parsing', ->
+    str = '( 3   ok-yes
+    "friend" )'
+    node = sexpr\match str
+
+    assert.is.equal '(', node.style
+    assert.is.equal 3, #node
+    assert.is.equal 3, node[1].value
+    assert.is.equal 'ok-yes', node[2].value
+    assert.is.equal 'friend', node[3].value
+
+    assert.is.equal str, node\stringify!
+
+  test 'tag parsing', ->
+    str = '([42]tagged 2)'
+    node = sexpr\match str
+
+    assert.is.equal '(', node.style
+    assert.is.equal 2, #node
+    assert.is.equal 'tagged', node[1].value
+    assert.is.equal 2, node[2].value
+
+    assert.is.equal 42, node.tag
+    assert.is.equal str, node\stringify!
+
+describe 'resynthesis', ->
+  test 'mixed parsing', ->
+    str = '( 3   ok-yes
+    "friend" )'
+    node = program\match str
+    assert.is.equal str, node\stringify!
+
+  test 'complex', ->
+    str = '
+  (osc "/radius" (lfo (cc 14)))
+
+  (osc rot
+    (step
+      (note "kick")
+      (random-rot)
+      (random-rot)
+      (random-rot)
+      (random-rot)
+    )
+  ) '
+    assert.is.equal str, (program\match str)\stringify!
diff --git a/test.alv b/test.alv
new file mode 100644
index 0000000..2514822
--- /dev/null
+++ b/test.alv
@@ -0,0 +1,17 @@
+(osc "/radius" (lfo (cc 14)))
+
+(set kick (note 38))
+(set pitch (const 440))
+
+(osc rot
+  (step
+    kick
+    (random-rot)
+    (random-rot)
+    (random-rot)
+    (random-rot)
+  )
+)
+
+(amp (env kick 02 10 05)
+     (sineosc pitch))