source: text-formbuilder/trunk/lib/Text/FormBuilder/grammar @ 80

# line directives
# block directives
# field lines
# comments

{
    #$::RD_TRACE = 1;
    my (
        @sections,     # master data structure
        $section_head,
        $section_id,
        @lines,        # lines in each section
        %lists,
        %patterns,
        %subs,         # validation subs
        @group,        # current group
        %groups,       # stored groups of fields
        $type,
        @options,
        $required,
        $list_var,
        $size,
        $maxlength,
        $rows,
        $cols,
        @submit,
    );
    my $context = 'line';       # start in line context by default
    my %formspec;
    
    # TODO: helper sub?
    sub alert ($) {
        warn '[' . (split(/::/, (caller(1))[3]))[-1] . '] ' . shift() . "\n";
    }
}

form_spec:
    { 
        %formspec = ();  # clear the old formspec data
    }
    (list_def | description_def | group_def | note | unknown_block_directive | line)(s)
    {
        # grab the last section, if there is any
        if (@lines) {
            push @sections,
                {
                    id   => $section_id,
                    head => $section_head,
                    lines => [ @lines ],
                };
        }
        
        $return = {
            title    => $formspec{title},
            author   => $formspec{author},
            description => $formspec{description},
            lists    => \%lists,
            patterns => \%patterns,
            subs     => \%subs,
            groups   => \%groups,
            sections => \@sections,
            ( @submit ? 
                (submit => @submit == 1 ? $submit[0] : \@submit) :
                ()
            ),
        }
    }

list_def: '!list' var_name (static_list | dynamic_list)
    { $lists{$item{var_name}} = [ @options ]; @options = () }

static_list: '{' /\s*/ option(s /\s*,\s*/) /,?/ /\s*/ '}'

dynamic_list: '&' <perl_codeblock>
    { warn "[Text::FormBuilder] Dynamic lists have been removed from the formspec grammar"; }

description_def: '!description' block
    {
        warn "[Text::FormBuilder] Description redefined at input text line $thisline\n" if defined $formspec{description};
        $formspec{description} = $item{block};
    }

group_def: '!group' { $context = 'group' } var_name '{' field_line(s) '}' { $context = 'line' }
    { 
        #warn "$item{var_name} group; context $context\n"
        $groups{$item{var_name}} = [ @group ];
        @group = ();
    }

note: '!note' block  { push @lines, [ 'note', $item{block} ]; }


# curly-brace delimited block, that can contain properly
# nested curly braces, along with any other characters
# inner blocks return with the '{...}' so that nested
# blocks get the braces treated as literals
block: '{' <skip:''> block_content(s) '}' { join('', @{ $item[3] }) }
inner_block: '{' <skip:''> block_content(s) '}'  { '{' . join('', @{ $item[3] }) . '}' }
block_content: /[^\{\}]+?/ | inner_block

# square brace delimited block, that can contain properly
# nested square brackets, along with any other characters
# inner bracket blocks return with the '[...]' so that nested
# blocks get the braces treated as literals
bracket_block: '[' <skip:''> bracket_block_content(s) ']' { join('', @{ $item[3] }) }
inner_bracket_block: '[' <skip:''> bracket_block_content(s) ']' { '[' . join('', @{ $item[3] }) . ']'; }
bracket_block_content: /[^\[\]]+?/ | inner_bracket_block


# field lines are the subset of lines that are allowed in a !group directive
field_line: <skip:'[ \t]*'> ( field | comment | blank ) "\n"

line: <skip:'[ \t]*'> ( title | author | pattern_def | section_head | heading | submit | group_field | field_group | unknown_directive | field | comment | blank ) /\n+/

title: '!title' /.*/
    {
        warn "[Text::FormBuilder] Title redefined at input text line $thisline\n" if defined $formspec{title};
        $formspec{title} = $item[2];
    }

author: '!author' /.*/
    {
        warn "[Text::FormBuilder] Author redefined at input text line $thisline\n" if defined $formspec{author};
        $formspec{author} = $item[2];
    }

pattern_def: '!pattern' var_name pattern
    { $patterns{$item{var_name}} = $item{pattern} }

pattern: /.*/

section_head: '!section' identifier /.*/
    {
        #warn "starting section $item{identifier}\n";
        #warn "  with heading $item[3]\n" if $item[3];
        
        if (@lines) {
            push @sections,
                {
                    id   => $section_id,
                    head => $section_head,
                    lines => [ @lines ],
                };
        }
        
        $section_id = $item{identifier};
        $section_head = $item[3];
        @lines = ();
    }

heading: '!head' /.*/    { push @lines, [ 'head', $item[2] ] }

submit: '!submit' string(s /\s*,\s*/)
    {
        #warn scalar(@{ $item[2] }) . ' submit button(s)';
        push @submit, @{ $item[2] };
    }

group_field: '!field' group_name name label(?)
    {
        warn "WARNING line $thisline: The '!field' directive has been DEPRECATED. Use the 'name:GROUP' style instead.\n";
        push @lines, [ 'group', { name => $item{name}, label => $item{'label(?)'}[0], group => $item{group_name} } ];
    }

group_name: /%[A-Z_]+/

field_group: name label(?) hint(?) group_type comment(?)
    {
        #warn "[$thisline] comment = $item{'hint(?)'}[0]\n" if $item{'hint(?)'}[0];
        #warn "[$thisline] field $item{name} is $item{group_type}\n";
        push @lines, [ 'group', {
            name    => $item{name},
            label   => $item{'label(?)'}[0],
            comment => $item{'hint(?)'}[0],
            group   => $item{group_type},
        } ];
    }

group_type: ':' var_name

# this is the real heart of the thing
field: name field_size(?) growable(?) label(?) hint(?) type(?) other(?) default(?) option_list(?) validate(?) comment(?)
    {
        my $field = {
            name     => $item{name},
            growable => $item{'growable(?)'}[0],
            label    => $item{'label(?)'}[0],
            comment  => $item{'hint(?)'}[0],
            type     => $item{'type(?)'}[0],
            other    => $item{'other(?)'}[0],
            value    => $item{'default(?)'}[0],
            list     => $list_var,
            validate => $item{'validate(?)'}[0],
            required => $required,
        };
        
        $$field{options} = [ @options ] if @options;
        
        $$field{rows} = $rows if defined $rows;
        $$field{cols} = $cols if defined $cols;
        $$field{size} = $size if defined $size;
        $$field{maxlength} = $maxlength if defined $maxlength;
        
        #warn "[$thisline] field $item{name}; context $context\n";
        if ($context eq 'group') {
            push @group, $field;
        } else {
            push @lines, [ 'field', $field ];
        }
        
        $type = undef;
        $required = undef;
        $list_var = undef;
        $size = undef;
        $rows = undef;
        $cols = undef;
        $maxlength = undef;
        @options = ();
        
        $field;
    }
    
name: identifier

var_name: /[A-Z_]+/

field_size: '[' ( row_col | size ) ']'

size: /\d+/ bang(?)
    { $maxlength = $item[1] if $item[2][0]; $size = $item[1] }

bang: '!'

row_col: /\d+/ /,\s*/ /\d+/
    { $rows = $item[1]; $cols = $item[3] }

growable: '*' limit(?) { $item{'limit(?)'}[0] || 1 }

limit: /\d+/

label: '|' string { $item[2] }

hint: bracket_block

type: ':' builtin_field

builtin_field: /textarea|text|password|file|checkbox|radio|select|hidden|static/

other: '+' 'other' { 1 }

default: '=' string { $item[2] }

string: simple_multiword | quoted_string

# for simple multiword values not involving punctuation
simple_multiword: /\w/ <skip:''> /[\w\t ]*/ { $item[1] . $item[3] }

# my attempt at a single-quoted, non-interpolating string
# where the backslash can escape literal single quotes
quoted_string: "'" <skip:''> /(\\'|[^'])*/ "'"
    { $item[3] =~ s/\\'/'/g; $item[3] }

option_list: options | list_var
    
options: '{' option(s /\s*,\s*/) '}'

list_var: /@[A-Z_]+/ { $list_var = $item[1] }

option: string display_text(?)
    { push @options, { $item[1] => $item{'display_text(?)'}[0] } }

value: identifier

display_text: bracket_block


validate: '//' (optional_pattern | required_pattern)

optional_pattern: var_name '?'  { $required = 0; $item[1] }

required_pattern: var_name { $required = 1; $item[1] }

comment: '#' /.*/
blank:

identifier: /\w+/

# skip unknown directives with a warning
unknown_directive: /\!\S*/ /.*/
    { warn "[Text::Formbuilder] Skipping unknown directive '$item[1]' at input text line $thisline\n"; }

unknown_block_directive: /\!\S*/ var_name(?) block
    { warn "[Text::Formbuilder] Skipping unknown block directive '$item[1]' at input text line $thisline\n"; }