source: text-formbuilder/trunk/lib/Text/FormBuilder/grammar @ 24

{ 
    my (
        $context,      # line or group
        @lines,        # master data structure
        $title,
        $author,
        $description,
        %lists,
        %patterns,
        @fields,
        @group,        # current group
        %groups,       # stored groups of fields
        @headings,
        $type,
        @options,
        $required,
        $list_var,
        $size,
        $rows,
        $cols,
    );
    $context = 'line';
}

form_spec: (list_def | description_def | group_def | line)(s) 
    {
        $return = {
            title    => $title,
            author   => $author,
            description => $description,
            lists    => \%lists, 
            patterns => \%patterns, 
            headings => \@headings,
            fields   => \@fields,
            lines    => \@lines,
            groups   => \%groups,
        }
    }

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

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

dynamic_list: '&' <perl_codeblock>
    {
        my @results = (eval $item[2]);
        if (ref $results[0] eq 'HASH') {
            @options = @results;
        } else {    
            @options = map { { $_ => $_ } } @results;
        }
    }

description_def: '!description' <perl_codeblock>
    { warn "[Text::FormBuilder] Description redefined at input text line $thisline\n" if defined $description;
    
    $description = $item[2];
    $description =~ s/^{\s*|\s*}$//g;
    }

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 = ();
    }

field_line: <skip:'[ \t]*'> ( field | comment | blank ) "\n"
line: <skip:'[ \t]*'> ( title | author | pattern_def | heading | group_field | unknown_directive | field | comment | blank ) "\n"

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

author: '!author' /.*/
    { $author = $item[2] }

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

pattern: /.*/

heading: '!head' /.*/
    {
        warn "[Text::FormBuilder] Header before field " . scalar(@fields) . " redefined at input text line $thisline\n" if defined $headings[@fields];
        $headings[@fields] = $item[2];
        push @lines, [ 'head', $item[2] ];
    }

group_field: '!field' group_name name label(?)
    { #warn "[$thisline] $item{group_name}\n"; 
    push @lines, [ 'group', { name => $item{name}, label => $item{'label(?)'}[0], group => $item{group_name} } ];
    }

group_name: /%[A-Z_]+/

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

var_name: /[A-Z_]+/

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

size: /\d+/
    { $size = $item[1] }

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

label: '|' (simple_multiword | quoted_string) { $item[2] }

hint: '[' /[^\]]+/ ']'    { $item[2] }

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

default: '=' (simple_multiword | quoted_string) { $item[2] }

# for simple multiword values not involving punctuation
simple_multiword: <skip:''> /[\w\t ]+/ { $item[2] }

# 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*/) '}'

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

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

value: identifier

display_text: '[' /[^\]]+/i ']'    { $item[2] }

validate: '//' (optional_pattern | required_pattern)    { $item[2] }

optional_pattern: /[A-Z_]+/ '?' { $required = 0; $item[1] }

required_pattern: /[A-Z_]+/ { $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"; }