Generate expression displays from compiled bytecode, not an ad-hoc parser

1 files changed, 91 insertions, 59 deletions

diff --git a/docs/tutorial/expression.html b/docs/tutorial/expression.html
index cea81292..22da2272 100644
--- a/docs/tutorial/expression.html
+++ b/docs/tutorial/expression.html
@@ -119,37 +119,37 @@
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-        <text x='70.875' y='105'>×</text>
-        <text x='92.375' y='57'>π</text>
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-        <text x='135.375' y='33'>2</text>
-        <text x='146.125' y='33'>⋆</text>
         <text x='156.875' y='33'>3</text>
+        <text x='146.125' y='33'>⋆</text>
+        <text x='135.375' y='33'>2</text>
+        <text x='113.875' y='57'>×</text>
+        <text x='92.375' y='57'>π</text>
+        <text x='70.875' y='105'>×</text>
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-        <text x='146.125' y='31'><tspan class='Function'>⋆</tspan></text>
         <text x='156.875' y='31'><tspan class='Number'>3</tspan></text>
+        <text x='146.125' y='31'><tspan class='Function'>⋆</tspan></text>
+        <text x='135.375' y='31'><tspan class='Number'>2</tspan></text>
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+        <text x='92.375' y='55'><tspan class='Number'>π</tspan></text>
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+        <text x='38.625' y='79'><tspan class='Number'>3</tspan></text>
+        <text x='27.875' y='79'><tspan class='Function'>÷</tspan></text>
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@@ -172,46 +172,46 @@
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         <text x='189.125' y='26'><tspan class='Number'>2</tspan></text>
+        <text x='178.375' y='26'><tspan class='Function'>√</tspan></text>
+        <text x='167.625' y='45'><tspan class='Function'>+</tspan></text>
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+        <text x='103.125' y='64'><tspan class='Number'>2</tspan></text>
+        <text x='92.375' y='64'><tspan class='Function'>√</tspan></text>
+        <text x='81.625' y='83'><tspan class='Function'>×</tspan></text>
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@@ -351,6 +351,38 @@
         <span class='Modifier2'>∘</span><span class='Function'>+</span>
     <span class='Number'>3</span>      <span class='Number'>4</span>
 </pre>
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+    <text><tspan class='Number'>3</tspan> <tspan class='Function'>×</tspan><tspan class='Modifier'>˜</tspan><tspan class='Modifier2'>∘</tspan><tspan class='Function'>+</tspan> <tspan class='Number'>4</tspan></text>
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+
 <p>This ordering is more consistent with the fact that the operand of a 1-modifier goes to its left. If we tried going from right to left we'd end up with <code><span class='Function'>×</span><span class='Paren'>(</span><span class='Modifier'>˜</span><span class='Modifier2'>∘</span><span class='Function'>+</span><span class='Paren'>)</span></code>, which uses <code><span class='Modifier'>˜</span></code> as an operand to <code><span class='Modifier2'>∘</span></code>. But a modifier can't be used as an operand. To make it work we'd essentially have to give 1-modifiers a higher precedence than 2-modifiers.</p>
 <p>In fact, the rules for modifiers are exactly the same as those for functions, but reversed. So why is there a distinction between 1- and 2-modifiers, when for functions we can look to the left to see whether there is a left argument? The reason is that it's natural to follow a 1-modifier by a subject or function that isn't supposed to be its operand. Using an example from the last section, <code><span class='Function'>+</span><span class='Modifier'>˜</span> <span class='Number'>3</span></code> has a subject to the right of the 1-modifier <code><span class='Modifier'>˜</span></code>. Even worse, <code><span class='Function'>+</span><span class='Modifier'>˜</span> <span class='Function'>÷</span> <span class='Number'>3</span></code> looks the same syntactically as <code><span class='Function'>+</span><span class='Modifier2'>∘</span> <span class='Function'>÷</span> <span class='Number'>3</span></code>, but it's two functions <code><span class='Function'>+</span><span class='Modifier'>˜</span></code> and <code><span class='Function'>÷</span></code> applied to <code><span class='Number'>3</span></code> while the version with Atop is a single function <code><span class='Function'>+</span><span class='Modifier2'>∘</span><span class='Function'>÷</span></code> applied to <code><span class='Number'>3</span></code>. So the two-layer system of functions and modifiers forces modifiers to have a fixed number of operands even every function (including those derived by applying modifiers) can be called with one or two arguments.</p>
 <p>Remember that 1-modifiers are all superscripts? The characters for 2-modifiers use a different rule: each contains an <em>unbroken</em> circle (that is, lines might touch it but not go through it). The 2-modifiers in BQN are the combinators <code><span class='Modifier2'>∘○⊸⟜⌾</span></code>, the sort-of-combinators  <code><span class='Modifier2'>⊘◶⍟</span></code>, and the not-at-all-combinators <code><span class='Modifier2'>⎉⚇⎊</span></code>. And the functions that make that unbroken circle rule necessary are written <code><span class='Function'>⌽⍉</span></code>. Since every primitive is a function, 1-modifier, or 2-modifier, you can always tell what type (and role) it has: a superscript is a 1-modifier, an unbroken circle makes it a 2-modifier, and otherwise it's a function.</p>