Generate a series of nested switch statements to parse CSSPrimitiveValue units.

third_party/WebKit/Source/build/scripts/templates/macros.tmpl

 {#
     FIXME: Do we need to put license blocks in generated files?
 #}
 {% macro license() %}
 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 {%- endmacro %}
+
+
+{% macro trie_leaf(index, object, return_macro, lowercase_data) %}
+{% for name, value in object.items() %}
+    {% if name|length %}
+if (
+        {%- for c in name -%}
+            {%- if lowercase_data -%}
+    {{ " && " if not loop.first }}toASCIILower(data[{{index + loop.index0}}]) == '{{c}}'
+            {%- else -%}
+    {{ " && " if not loop.first }}data[{{index + loop.index0}}] == '{{c}}'
+            {%- endif -%}
+        {%- endfor -%}
+    )
+    return {{ return_macro(value) }};
+break;
+    {% else %}
+return {{ return_macro(value) }};
+    {% endif %}
+{% endfor %}
+{% endmacro %}
+
+
+{% macro trie_switch(trie, index, return_macro, lowercase_data) %}
+{% if lowercase_data %}
+switch (toASCIILower(data[{{index}}])) {
+{% else %}
+switch (data[{{index}}]) {
+{% endif %}
+{% for char, value in trie.items()|sort %}
+case '{{char}}':
+    {% if value|length == 1 and value.items()[0][1] is string %}
+    {{ trie_leaf(index+1, value, return_macro, lowercase_data) | indent(4) }}
+    {% else %}
+    {{ trie_switch(value, index + 1, return_macro, lowercase_data) | indent(4) }}
+    {% endif %}
+{% endfor %}
+}
+break;
+{% endmacro %}
+
+
+{% macro trie_length_switch(empty_case_return_value, length_tries, return_macro, default_return_value, lowercase_data) %}
+switch(length) {
+{% if empty_case_return_value %}

[Timothy Loh, 2016/05/12 07:03:14]

This shouldn't be needed any more due to
https://codereview.chromium.org/1952973002

[meade_UTC10, 2016/05/13 03:48:19]

Done.

+case 0:
+    return {{ empty_case_return_value }};
+{% endif %}
+{% for length, trie in length_tries %}
+case {{ length }}:
+    {{ trie_switch(trie, 0, return_macro, lowercase_data) | indent(4) }}
+{% endfor %}
+}
+return {{ default_return_value }};

[Timothy Loh, 2016/05/12 07:03:14]

I think it'd be nicer if the users of the macro just write the return
themselves.

[meade_UTC10, 2016/05/13 03:48:19]

Done.

+{% endmacro %}