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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/spec/grammar.html | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/docs/spec/grammar.html b/docs/spec/grammar.html index 9f99b430..3b18a102 100644 --- a/docs/spec/grammar.html +++ b/docs/spec/grammar.html @@ -44,12 +44,17 @@ </span><span class='Function'>FuncExpr</span> <span class='Function'>=</span> <span class='Function'>Train</span> <span class='Function'>|</span> <span class='Function'>F</span> <span class='Function'>ASGN</span> <span class='Function'>FuncExpr</span> </pre> -<p>Subject expressions are complicated by the possibility of list and namespace assignment, which share the nodes <code><span class='Value'>lhsList</span></code> and <code><span class='Value'>lhsStr</span></code> and cannot be completely distinguished until execution. We also define nothing-statements, which have very similar syntax to subject expressions but do not permit assignment.</p> +<p>Subject expressions consist mainly of function application. We also define nothing-statements, which have very similar syntax to subject expressions but do not permit assignment. They can be used as an <code><span class='Function'>STMT</span></code> or in place of a left argument.</p> <pre><span class='Value'>arg</span> <span class='Function'>=</span> <span class='Value'>subExpr</span> <span class='Function'>|</span> <span class='Paren'>(</span> <span class='Value'>subject</span> <span class='Function'>|</span> <span class='Value'>nothing</span> <span class='Paren'>)</span><span class='Value'>?</span> <span class='Function'>Derv</span> <span class='Value'>arg</span> <span class='Value'>nothing</span> <span class='Function'>=</span> <span class='String'>"·"</span> <span class='Function'>|</span> <span class='Paren'>(</span> <span class='Value'>subject</span> <span class='Function'>|</span> <span class='Value'>nothing</span> <span class='Paren'>)</span><span class='Value'>?</span> <span class='Function'>Derv</span> <span class='Value'>nothing</span> -<span class='Function'>NAME</span> <span class='Function'>=</span> <span class='Value'>s</span> <span class='Function'>|</span> <span class='Function'>F</span> <span class='Function'>|</span> <span class='Modifier'>_m</span> <span class='Function'>|</span> <span class='Modifier2'>_c_</span> +<span class='Value'>subExpr</span> <span class='Function'>=</span> <span class='Value'>arg</span> + <span class='Function'>|</span> <span class='Value'>lhs</span> <span class='Function'>ASGN</span> <span class='Value'>subExpr</span> + <span class='Function'>|</span> <span class='Value'>lhs</span> <span class='Function'>Derv</span> <span class='String'>"↩"</span> <span class='Value'>subExpr?</span> <span class='Comment'># Modified assignment +</span></pre> +<p>The target of subject assignment can be compound to allow for destructuring. List and namespace assignment share the nodes <code><span class='Value'>lhsList</span></code> and <code><span class='Value'>lhsStr</span></code> and cannot be completely distinguished until execution. The term <code><span class='Value'>sl</span></code> in <code><span class='Function'>LHS_SUB</span></code> is used for header inputs below: as an additional rule, it cannot be used in the <code><span class='Value'>lhs</span></code> term of a <code><span class='Value'>subExpr</span></code> node.</p> +<pre><span class='Function'>NAME</span> <span class='Function'>=</span> <span class='Value'>s</span> <span class='Function'>|</span> <span class='Function'>F</span> <span class='Function'>|</span> <span class='Modifier'>_m</span> <span class='Function'>|</span> <span class='Modifier2'>_c_</span> <span class='Function'>LHS_SUB</span> <span class='Function'>=</span> <span class='String'>"·"</span> <span class='Function'>|</span> <span class='Value'>lhsList</span> <span class='Function'>|</span> <span class='Value'>sl</span> <span class='Function'>LHS_ANY</span> <span class='Function'>=</span> <span class='Function'>NAME</span> <span class='Function'>|</span> <span class='Function'>LHS_SUB</span> <span class='Function'>|</span> <span class='String'>"("</span> <span class='Function'>LHS_ELT</span> <span class='String'>")"</span> <span class='Function'>LHS_ATOM</span> <span class='Function'>=</span> <span class='Function'>LHS_ANY</span> <span class='Function'>|</span> <span class='String'>"("</span> <span class='Value'>lhsStr</span> <span class='String'>")"</span> @@ -59,10 +64,7 @@ <span class='Value'>lhsList</span> <span class='Function'>=</span> <span class='String'>"⟨"</span> <span class='Separator'>⋄</span><span class='Value'>?</span> <span class='Paren'>(</span> <span class='Paren'>(</span> <span class='Function'>LHS_ENTRY</span> <span class='Separator'>⋄</span> <span class='Paren'>)</span><span class='Value'>*</span> <span class='Function'>LHS_ENTRY</span> <span class='Separator'>⋄</span><span class='Value'>?</span> <span class='Paren'>)</span><span class='Value'>?</span> <span class='String'>"⟩"</span> <span class='Value'>lhsComp</span> <span class='Function'>=</span> <span class='Function'>LHS_SUB</span> <span class='Function'>|</span> <span class='Value'>lhsStr</span> <span class='Function'>|</span> <span class='String'>"("</span> <span class='Value'>lhs</span> <span class='String'>")"</span> <span class='Value'>lhs</span> <span class='Function'>=</span> <span class='Value'>s</span> <span class='Function'>|</span> <span class='Value'>lhsComp</span> -<span class='Value'>subExpr</span> <span class='Function'>=</span> <span class='Value'>arg</span> - <span class='Function'>|</span> <span class='Value'>lhs</span> <span class='Function'>ASGN</span> <span class='Value'>subExpr</span> - <span class='Function'>|</span> <span class='Value'>lhs</span> <span class='Function'>Derv</span> <span class='String'>"↩"</span> <span class='Value'>subExpr?</span> <span class='Comment'># Modified assignment -</span></pre> +</pre> <p>A header looks like a name for the thing being headed, or its application to inputs (possibly twice in the case of modifiers). As with assignment, it is restricted to a simple form with no extra parentheses. The full list syntax is allowed for arguments. A plain name is called a label and can be used for a block with or without arguments. First we define headers <code><span class='Function'>IMM_HEAD</span></code> that include no arguments.</p> <pre><span class='Value'>headW</span> <span class='Function'>=</span> <span class='Value'>lhs</span> <span class='Function'>|</span> <span class='String'>"𝕨"</span> <span class='Value'>headX</span> <span class='Function'>=</span> <span class='Value'>lhs</span> <span class='Function'>|</span> <span class='String'>"𝕩"</span> |